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Dave miller
24th October 2008, 06:24 AM
In another thread Percepts raises questions that partly encompass enlarger types. So, I thought I would open a discussion specifically on that point.

I have only ever used a colour head diffusion enlarger, so the following comments must be tempered by this statement.

I have never seen any reliable evidence that any other type of enlarger illumination will produce visibly better prints. Can anyone demonstrate otherwise?

Argentum
24th October 2008, 07:00 AM
Define "Visibly Better" and that will be the crux of the case for or aginst any type of enlarger.

If you read the Durst literature for a varipoint head for an L1200, then you will see that a point source head with optically coated condensors is the way to go for obtaining the finest detail in a print. But that doesn't mean it is automically a "Visibly Better" print. For example, a head shot of an elderly woman photographed with the sharpest macro lens and then printed with a point source enlarger head so that it shows every wrinkle, crevice, skin pore and zit would not be very flattering. So how do you judge what is a "Visibly Better" print.
On the other hand, if you were printing the result from and electron microscope so that you could see the structure of a crystal, then a soft working diffusion head wouldn't work as well as a point source head.
There is a distinction to be made between technically better and aesthetically better and that depends upon purpose, personal and artistic taste and also anticipated subject taste.

A normal condensor enlarger is somewhere between the two.

The durst literature is here: www.darkroom.ru/info/brochures/durst_enlargers/consumer_e.pdf

Dave miller
24th October 2008, 08:08 AM
For the purpose of this discussion I would like to put Scientific at one end of a long scale and Artistic at the other, and keep the discussion more towards the artistic end for I believe that’s where most of our interests lie.

I have read the Durst literature in the past and assumed that their specialist light sources were aimed at the scientific community.

My interest is with the hobbyist, and professional commercial photographer who may still print properly.

So for the average portrait, flower study, or landscape will I see a difference in a normal print at normal viewing distances?

RH Designs
24th October 2008, 08:14 AM
Provided the prints are made to the same contrast then no, you won't. IMHO :)

Ag-Bromide
2nd November 2008, 05:58 PM
My first enlarger was a Meopta condenser enlarger followed by an LPL colour enlarger, I sold both of those for my current Durst enlarger which is fitted with a VC module. I no longer make colour prints and would never go back to using a colour module.
I see no difference in sharpness between them.

big paul
14th January 2009, 03:27 PM
hi dave
I have used condenser and diffusion enlargers and I like the condenser system the most it seems to give me more contrast,when I want it. my main enlarger is a lpl 7700 pro with triple condenser head fitted, I also have the colour head with transformer .
I use graded paper most of the time which seems to work better with a condenser set up.
its our hobby and we do what pleases us the most, so what ever rocks your boat(or dev tray) as they say. after 40 odd years messing about in the darkroom this way of doing things suits me .

Dave miller
14th January 2009, 05:06 PM
hi dave
I have used condenser and diffusion enlargers and I like the condenser system the most it seems to give me more contrast,when I want it. my main enlarger is a lpl 7700 pro with triple condenser head fitted, I also have the colour head with transformer .
I use graded paper most of the time which seems to work better with a condenser set up.
its our hobby and we do what pleases us the most, so what ever rocks your boat(or dev tray) as they say. after 40 odd years messing about in the darkroom this way of doing things suits me .

I quite agree Paul, wouldn't it be a boring world if we all did things the same way.

kennethcooke
14th January 2009, 06:00 PM
Following on from the above comments I am leaning towards a s/hand Leitz Focomat V35 AF enlarger and lens offered through Nova for £385.00 http://www.novadarkroom.com/product/651/SH_Leitz_Focomat_V35_AF.html which would seem to fulfill all my needs. I was interesting to note the early experiences of members in an adjacent thread. I am proposing to use a very dry cellar in our 19th century Yorkshire stone house but I will need to go up two flights of stairs to the bathroom to wash my prints. Not ideal but it will give me good exercise. My other choice of location could be our daughters bedroom, she has now moved out by the way, which means only a short walk along the landing but I would need to rig up some sort of blackout

B&W Neil
14th January 2009, 07:26 PM
Having used various makes of condensor and colour head enlargers over the years for my mono work, all of which I found very good in their time, I now only use a De Vere with an Ilford 500H MC head. The De Vere is as joy to use with the bench handle sizing and focus controls, no filters to turn or place in and the negs stay in focus. However, I wouldn't say it creates better prints but as it is designed for pro use and is so easy to use it does free up my creative side to concentrate on making prints. A thing not to be overlooked with enlargers is the lens of course - that is probably the most important part of an enlarger. Many years ago I graduated from a good budget lens to my first Nikon and I just could not believe the difference it made. Maybe we could also have a discussion on enlarging lenses?

Neil.

André.E.C.
15th January 2009, 01:29 AM
I've always used condensers, started with an old Durst F60 and one Meopta Magnifax 4a. Somehow I prefer the sharp, crispy and punchy look of the prints produced by condenser units, rather the softer, maybe more balanced ones, I've made with colour heads. Downsides? You bet, scratched or dusty negatives, a true nightmare.

Which one is better? Both are great.

3 days ago, I let the 2 oldies retire after some very honourable service, lately, the F60 was used to flash paper and the Magnifax was unused. My present darkroom is too small for 2 enlargers, so I invested the incredible sum of 140 euros on an almost new Durst M805 unit. One all around unit in, 2 oldies out, problem solved. As for optics, I'm using 3 EL-Nikkors, one 50mm f/2.8, one 80mm f/5.6 and one 105mm f/5.6, all of them N series.


Cheers



André

Peter Hogan
15th January 2009, 08:28 AM
I never use a colour head (or the filters within it) for B&W work; always Ilford contrast filters. It's what I prefer. Enlarger-wise I use either a condenser or diffuser, depending on the neg and the 'look' I want.

Martin Aislabie
15th January 2009, 05:44 PM
I have a Kaiser 9005 Condenser Enlarger for my 35mm - 6x9 negs

I have always used a Below the Lens set of MG Filters.

I also now have a DeVere 504 with Colour Head but I am still use the Below the Lens Filter Set (not convinced I have the dexterity to move the colour dials without disturbing the head - but can carefully change the MG Filters by gingerly sliding them in & out)

I have yet to try printing the same neg on both machines to see the effect of contrast between the Condenser (Kaiser) and Diffusion (DeVere)

It’s on my “to do sometime” list – but I always have lots more fun things to do in the darkroom first.

However, the Kaiser isn't a true condenser system, as it uses a frosted bulb and the lamp house has many white reflective surfaces to re-direct the light into the Condenser lens set - so its more of a half way house between a true Condenser System and an all out Diffuser.

Martin

Richard Gould
19th January 2009, 07:42 PM
I always use a condencer system,I find the grittines and sharpness suits my style,and I like to use the ilford above lens filters. I use a meopta opemus 6 with glassles neg carrieres( ANYTHING TO REDUCE DUST) with a meopta meogan 80mm for medium format and a enikkor for 35 mm.Richard

Les McLean
19th January 2009, 11:27 PM
For most of my photographic life I've been a fan of cold cathode enlargers and currently use a Zone VI VC Cold Cathode. I need to produce negatives with about 1 stop more contrast than a normal condensor negative but that's no problem. Used in conjunction with RH Designs StopClock Compensating Timer I think it's the best combination available.
Enlarging lens are Nikon 50mm and 80mm for 35mm and 120 and Schnieder 150mm for 5 x 4.

David Lingham
20th January 2009, 08:31 AM
About 35yrs ago I started with a small Durst F30, that was a condenser enlarger. After a few years I bought a Devere 203 with a cold cathode head, and saw an immediate change in the tonality and detail of my prints, I also learned that I needed to produced negs that had more contrast. Back then I only used graded paper, now that I use mostly VC paper, I've added a dichro head to my 203 along with an RH timer. Also I still use the same 50mm el-Nikkor I had with my early Durst

Dave miller
20th January 2009, 09:04 AM
For the purpose of this discussion I would like to put Scientific at one end of a long scale and Artistic at the other, and keep the discussion more towards the artistic end for I believe that’s where most of our interests lie.

I have read the Durst literature in the past and assumed that their specialist light sources were aimed at the scientific community.

My interest is with the hobbyist, and professional commercial photographer who may still print properly.

So for the average portrait, flower study, or landscape will I see a difference in a normal print at normal viewing distances?

So far I think we have had some very interesting input to this thread, but nothing to demonstrate that it is worthwhile for me to change my colour head enlarger, for which I should be thankful I suppose. :)


Has anyone ever done a side-by-side test, or will the apparent requirement to produce negatives of a specific contrast for each type preclude that?

Trevor Crone
20th January 2009, 10:53 AM
FWIW; I've now settled on a DeVere 504 with 500MG head. It suits my style of printing with the ease at which it allows split grade printing.

It uses two lamps in combination, green=soft, blue=hard, and any combination in between. Because all controls are on the keypad there is no need to touch the head except to manouver the under lens light-safe swing filter. I also have the footswitch fitted which is a great help when I needs my hand free to manipulate the image.

I can set the grades from 0 to 5 + 1/2 stops.

The baseboard controls of both head hight and focusing are an absolute joy, they can be locked in position for added stability.

Anyone contemplating such an enlarger, all I can say is know is the time to buy.

Before this I used a Magnafax 4 with Meograde VC head which probably gave slighty harder prints grade for grade, but certainly no more then 1/2 grade.

Steven Taylor
20th January 2009, 12:16 PM
FWIW, I use a DeVere 504 with a Dichromat head, I have a 504 which is fitted with a cold cathode head but I find it very slow. In years gone by I have used both cold and condenser heads on 504's and 54's. When I have taught in uni's, art schools and community darkrooms they have often been fitted with a miss match of hobby type enlargers that usually have either condenser or on occasions diffuser heads. So I guess I've tried most options and my preference is the Dichromat. I haven't used a multigrade head but I understand from others that it is a good solution. The 504 locks down really tight so dialing filtration in and out does not present any problems. I often use different filtration for different parts of the neg. I have always fancied a focomat, but I don't really know why.
Steven

Argentum
20th January 2009, 05:44 PM
One benefit of using an enlarger which requires a harder contrast negative is that obtaining that harder contrast in the negative also gives better film speed. Probably of no major benefit for landscape work where camera is on a tripod, but for hand held work, then an extra half stop or more of speed can make a big difference.

Victor Krag
23rd January 2009, 06:33 PM
I wish I knew which Dursts, Meoptas, and Deveres were condenser or diffusion so to better understand the posts. I've been very happy with the LPL6700 Dichro diffusion that I first owned for up to 6x7cm negs and then followed by the LPL D4500 (Dichro diffusion) for up to 4"x5". John Sexton is a devout LPL Dichro Diffusion user and the recent work I've of his is so sharp, they cut my optic nerves! Seriously, the prints are so sharp, it's almost unpleasant.

Argentum
23rd January 2009, 06:58 PM
I wish I knew which Dursts, Meoptas, and Deveres were condenser or diffusion so to better understand the posts. I've been very happy with the LPL6700 Dichro diffusion that I first owned for up to 6x7cm negs and then followed by the LPL D4500 (Dichro diffusion) for up to 4"x5". John Sexton is a devout LPL Dichro Diffusion user and the recent work I've of his is so sharp, they cut my optic nerves! Seriously, the prints are so sharp, it's almost unpleasant.

Nearly all dursts have the option or either dichro diffusion or condensor as there were two or three or four heads for each of them. E.g. the modular 70 has 4 possible heads including a fully electronic one for colour.

Roy_H
23rd January 2009, 07:30 PM
Like Steven, my preference is for the De Vere Dichromat head, which I have on a 507 floor-standing model. But that's for the big stuff, for 35mm to 6x7 I use a De Vere 203 bench enlarger with a Multigrade 500H head and, I have to admit, I find it a great deal easier than dialling in M/Y settings on the Dichromat.

One accessory for the 507 that I do have, but haven't used for years, is a point-source lamp housing and controller. I used to use it at work for printing autoradiographs and photomicrographs, to get maximum contrast and definition. It tried it for my own work, but found it such a pain to set up that I didn't pursue it. It did produce some amazingly sharp results though, but it also emphasised every tiny particle of dust or imperfection on the negative - and on the condensers as well!

I maybe should try it out again sometime for old times sake and wondered if anyone else here had ever used one?

Tony lovell
6th February 2009, 11:03 PM
I’m in the process of setting up a new darkroom and I’m considering the purchase of a reconditioned DeVere 5108 vertical floor standing enlarger with Dichromat head, I think was the last model made, and its in good condition, does any one have any experience of this enlarger? I guess it’s very similar to the 507?

I shoot both 7 x 5 and 10 x 8 regularly, but it would just be used for the 10 x 8 B&W negative work.

Tony

du a gwyn
7th February 2009, 09:34 PM
for all my stuff up to 6x9 i use my de vere 203 fitted with the ilford 500.for the first few weeks after i bought it i used the ilford control panel,but after using rh design timmers for many years i just couldn't do with out it.so i had to buy the rh design timmer dedicated to the 500 head and it was back to heaven again!
for anything larger i use de vere 507(bench model) with a colour head and under the lens filters,far easier.i would like to get a 500 head to fit this so i can use the rh timmer on both the enlargers.just waiting now for more people to go 'D' so i can pick one up cheap.anybody got one hiding underneath there bench that needs a good home.
diolch.

JOReynolds
2nd December 2013, 06:39 PM
When discussing the differences between diffuse and condenser lightsources, a distinction must be made between types of condenser enlarger. Point-source enlargers incorporate no diffusion at all and require a change of condensers (Durst, De Vere, Omega) or lamp position (Beseler) when changing lenses. Enlargers using 75 or 150watt opal bulbs usually allow for both 50mm and 80mm lenses without adjustment and share some characteristics with fully-diffused lightsources.

sbandone
7th December 2013, 04:13 PM
A few thoughts on enlargers which may help - I have the privilege of owning several enlargers:-
De Vere 504 with various heads Multigrade 500H, Varicon condenser, Cathomag, Dichro mk 4 Colour
Durst L1000 Laborator with Condensors - reflex lighting
Leitz Valoy 35mm Condensor
Kaiser 7005 with Multigrade, BW Condensor and Colour Heads
I did have more but sold them!
I have done quite a number of tests over time for both sharpness of detail, microcontrast and overall tonality, using "normally exposed and processed negatives", and also negative popping through temperature change

My conclusions:-
There is a difference in contrast between the condensor and diffusion enlargers, but no real resultant difference in sharpness - any perceived improvement in sharpness would be down to greater microcontrast using a condensor head. A smoother tonality can be seen on prints when using the Dichro diffuser head - it is especially useful for landscapes where there are a range of subtle highlights - as better highlight detail can be seen. For scenes where there is a large area of water present then printing using a condensor will give a more punchy result. I estimate that for a given negative there is about 1 Grade of difference between condenser and diffuser enlargers - Diffuser requires harder Grades. Dichro Heads are not capable of delivering a true Grade 5 so a supplementary MG 5 Filter will be required. Of course you can use the white light setting with underlens filters and get 00-5 but lose a wisp of sharpness
For ease of use there is little to equal the De Vere 504 with Multigrade Head using either the original 500CPM Control Box Grades 0-5 in half grades, or the RH F Stop Professional Timer designed for the 500H where Grades 00-5 are obtainable in 1/10 Grades. I have found that the strength of a condensor enlarger is in producing a bright print with good shadow detail - I have found this more difficult to achieve with the 500CPM Control Unit as often shadows became blocked, but excellent results can be achieved with the RH Unit where fine control of contrast of both highlights and shadows is possible.

My condensor heads are now safely in the loft as I use both the De Vere 500H or Dichro Heads. There are other factors for sharpness to be taken into consideration - vibrations - and negative popping through heat gradients. I had a significant negative movement problem with the De Vere Varicon head that only the use of a full glass negative carrier could correct. The Durst L1000 by comparison was totally stable as it employs reflex lighting and a heat filter - so it in some ways is better than the De Vere where a condensor style print is required
The Leitz Valoy is a capable 35mm enlarger - the negative is held flat in the carrier by a condenser and produces very sharp and tonally balanced prints without negative popping - trouble is you've got to use underlens MG filters for multigrade papers which can be tricky to mount

The Kaiser is a capable enlarger especially with a VC MG Head using reflex lighting and a combination of diffuser and condensors, but in my view does not equal the capability of the De Vere 504 in terms of evenness of illumination, stability, repeatability of setting grades, or lack of negative movement during exposure. There is no advantage in trying to use the colour head for BW prints rather than the VC head. The BW direct illumination head overheats the negatives and causes popping even using a heat filter (admittedly it was from a Meopta)
As for the Cathomag Head on the DV504 - This could be good but I have found it difficult to get repeatable results as the exposure times can produce different results - guess this needs a shuttered lens assembly and keep the enlarger lamp on all the time - so It's also in the loft!

Hope this helps

dsallen
7th December 2013, 04:43 PM
From the very day that I tried out a friend's (then) brand new De Vere 504 with Ilford 500 head I was hooked. It doesn't produce necessarily 'better' prints than any other set-up but it makes it very easy to get the results I want. After I bought one, within weeks the de Beers soft/hard developers were gaining dust because I didn't need them any more. The pre-flashing diffuser (mounted where the red filter used to be) was taken off the enlarger and soon lost with no regrets. With the (later model) controller I can programme a number of exposures to easily get the print I want (e.g. for an interior scene maybe printing the shadows hard and the windows on a softer grade). When I worked commercially and had to produce literally 100s of prints per day the programmable keypad was a real sanity saver!

I like my prints to look contrasty but with detail throughout. In general, I achieve this by printing at grade 3.5 and then selectively adding in a little bit of grade 5 and, on occasions adding a little bit of grade 1 to the edges of the image to bring down the bright highlights where they meet the border. Doing this is very easy with no need to change filters for each stage of the process or dialing different filtrations on a colour head.

Finally, as someone who hates spotting with a vengeance, I stopped using condenser enlargers after my first experience with using a Lines & Jones fitted with a Cold Cathode head.

So technically my set-up no better than any other set-up but a whole lot easier to get the results that I want - perhaps that can be seen in the prints or, more probably, in the number of successful prints that I can achieve in comparison to any of the other set-ups that I have used in the past..

Bests,

David
www.dsallen.de

Argentum
7th December 2013, 05:58 PM
In pursuit of clarifying any potential confusion...


Dichro Heads are not capable of delivering a true Grade 5 so a supplementary MG 5 Filter will be required.

The above statement is dependant on your enlarger, the filters it has in it and the freshness of your paper. I have conclusively proved that a Durst L1200 with CLS501 head is capable of producing ISO grade 5 on MGIV current papers(not tested brand new Classic version).

See:

http://www.film-and-darkroom-user.org.uk/forum/showpost.php?p=8283&postcount=60

and

http://www.film-and-darkroom-user.org.uk/forum/showpost.php?p=8285&postcount=62

A point which very recently came up is that older MG papers (MG III and earlier) used different filter sets which won't produce ISO G5 on current papers. It is entirely feasible that older ILFORD heads (and other manufacturers heads) have filtering designed for MG III or earlier which won't give you G5 on current papers.

So your above statement really needs to specify which papers the filter sets in your enlargers were designed for.

Otherwise good info.

Argentum
7th December 2013, 08:12 PM
Kaiser 7005
The BW direct illumination head overheats the negatives and causes popping even using a heat filter (admittedly it was from a Meopta)


Is the lamp on the BW head (not the VC head) directly vertical above the negative or is there a reflex mirror?
And is there a diffusion sheet in the light path?

This was an enlarger I was considering for future use but have never actually seen one in the flesh. I presumed there was a reflex mirror.

Thanks

sbandone
8th December 2013, 12:09 AM
Thanks Argentum
The Dichro Head I referred to was in fact the De Vere Dichro mk4 which uses Kodak filter gradations YMC 0-200. Any tests were based on current fresh Ilford Multigrade 4 RCVC and FBVC papers

A propos the Kaiser 7005 with BW Head 4541 the 75w opal bulb is directly above the condenser. Perhaps if I had forked out £80 for a Kaiser heat filter, the problem might have gone! But I used a lower cost Meopta option without much success

Hope this clarifies

JOReynolds
8th December 2013, 01:41 PM
I have conclusively proved that a Durst L1200 with CLS501 head is capable of producing ISO grade 5 on MGIV current papers.
How can I conclusively replicate the method of measuring ISO contrast grades. I believe that I am suitably equipped, with stepwedges, densitometer, several lightsources including Multigrade 500H, tungsten with Ilford Multigrade filters and 430nm LEDs.

Argentum
8th December 2013, 03:36 PM
set your enlarger on softest grade (0 or 00).

Take you step wedge and print some test strips until you find a print time where the full step wedge is printed from black to white in the middle. i.e. you have more than one black step at one end and more than one white at the other end.

Then keeping time the same for all further prints, print at each grade from 00 to 5 and a final print with 0 filtration.

Then with your densitometer you measure and plot in an excel spreadsheeet graph each of the readings and voila you have a chart.

The cutoff at the bottom of the chart is 0.04 logD above Dmin and the cutoff at the top of the chart is 90% of Dmax.
then you can measure the distance allong bottom of chart to find the exposure log range between the bottom and top cutoffs where the curve passes through them.
That distance between the two is for example 0.88 Log Exposure. You multiply that number by 100 and that give you the ISO(R) grade of the curve.

The graphing is all explained in Steve Anchell book "The variable contrast printing manual" ISBN 0-240-80259-4

And you MUST use paper as close to manufacture as possible for best results. Old paper loses contrast badly and so results from old paper don't represent what paper is really capable of.

If you PM me your email address I will send you a sample excel spreadsheet which may help you. But be warned you must have some skill at using excel spreadsheet graphs to get it to work.

Argentum
8th December 2013, 05:32 PM
p.s. If using MG filters (not dichro) remember to double exposure time for grades 4 and up.

Argentum
9th December 2013, 12:29 PM
Perhaps I should add that the x-axis should be the density steps of your step wedge and the y-axis the density of print from each step of the wedge.
This requires a step wedge with known density differences. Mine has 0.1 steps. Some have 0.15 steps which should work just as well for this purpose.

Miha
9th December 2013, 06:10 PM
I'm using a Kaiser V-system colour enlarger. The source of ilumination is a 100 W halogen lamp. There is no heat reaching the nagative and I have certainly never experienced the neg to pop in my glassless negative carrier even when exposing for more than 60 seconds (Fomatone 12x16).

Argentum
9th December 2013, 06:18 PM
I think the difference is the that the VC version uses a reflex mirror (I think) whereas the BW condensor head has the bulb in a direct line with the neg and much closer I would hazard a guess. so it will transfer a lot more heat.

Miha
9th December 2013, 06:23 PM
I think that all variants use a reflex mirror, judging by the shape of the head.

Argentum
9th December 2013, 06:24 PM
I think that all variants use a reflex mirror, judging by the shape of the head.

I thought that but asked the question and the answer was that the B+W head is different.

Miha
9th December 2013, 06:29 PM
True. See page 36: http://www.kaiser-fototechnik.de/pdf/anleitungen/4420_4.pdf

sbandone
10th December 2013, 06:36 PM
Hi Miha and Argentum
I have copied a previous post I made which shows some practical results using De Vere and Kaiser enlargers and hope it might be of some help

I mainly use De Vere 504 enlargers and have experienced a problem of print fuzziness through negative popping - this problem was evident using the Varicon head using glassless neagtive carriers- after focusing on the grain using a good grade focusing aid the negative went out of focus as the lamp heated up (You could time it typically after 20secs) - I unsuccesfully tried to obtain a heat filter 15x15cm and contacted Odyssey and Lightwave - the advice given to me by Lightwave was to remove the negative carrier and focus the lamp on to the baseboard and try to eliminate the red and cyan fringing by altering the position of the bulb.
Did it work - well slightly!
I then started using the negative carrier with Anti Newton Glass on top of the negative and plain glass underneath - the problem went instantly

I also use the Dichro and Multigrade heads -whilst I can use these more successfully with glassless carriers there can still be a slight movement of the negative especially if a lot of burning in is being done
You can get movement of the negative after 1-2mins continuous lamp running

So I now always use glass top and bottomwith all De Vere enlarger and heads, and I change the light mixing box or condensors to match the negative format

This problem also manifested itself with a Kaiser enlarger using a MG Head and glassless inserts

My results were:-( You can see I had a problem!)
1. 35mm format using 35mm condensor- glassless inserts in carrier with heat filter in filter drawer- No movement of focus after 3 minutes continuous lamp running
2. 35mm format using universal carrier with AN glass top insert and glassless inset lower - without heat filter in drawer - focus shift after 15 secs
3. As 2 but with heat filter movement after 1m 15 secs
4. AN glass top and plain glass lower with heat filter - no movemnt after 3 minutes continuous running
5. Similar results were obtained using 645 and 67 negatives and their matching condensors

Conclusions -
1. Match the condensor to the negative size - thus reducing the excess heat transmitted to the negative and minimising the exposure time.
2. The use of anti newton glass on the top and plain glass inserts in a universal negative carrier, with the heat filter in the drawer eliminates the problem
3. Note that on the 35mm format only - it was possible to get no focus shift after 3 minues using correctly assembled glassless inserts and the 35mm condendor and a heat filter in place

I hope this sheds a some light on this for you!

BTW I never experienced this problem using the Kaiser colour head fro colour printing but colour exposure times are much shorter normally. I tried using the head for BW printing but quickly reverted to the MG head - easier!

Argentum
10th December 2013, 06:48 PM
Thanks, useful info,

I use Durst L1200 with cls501 dichro filters or sometimes under the lens MG filters.
never noticed a problem with neg popping but have noticed that AN glass causes effects in print so I don't use it unless absolutely necessary (curly negs).