Support our Sponsors, they keep FADU free:   AG Photographic   The Imaging Warehouse   Process Supplies   RH Designs   Second-hand Darkroom Supplies  

Notices

Go Back   Film and Darkroom User > Equipment > Darkroom

  ***   Click here for the FADU 2015/2014 Yearbooks   ***

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 23rd October 2021, 08:47 PM
John King John King is offline
Friend
 
Join Date: Nov 2012
Location: County Durham
Posts: 3,319
Default Multigrade

With all the chatting about colour filtration values when using a colour head on an enlarger. The double filtration values for Ilford MG5 I think from Grade 1.5 to 3.5 will, we assured, if we swap from 1.5 to 3.5 the exposure will remain the same (supposedly).

In theory then, if someone with a non colour head were to use the individual filters sold by Ilford in half grades from 00 to 5 is it known if the same exposure theory applies as well?

Do they have the same values as the double filtration using Yellow or Magenta?
Reply With Quote
  #2  
Old 24th October 2021, 11:41 AM
Mike O'Pray Mike O'Pray is offline
Friend
 
Join Date: Oct 2008
Location: Daventry, Northants
Posts: 8,969
Default

John, I do not have any MG5 but is the information leaflet you get with MG5 have the same dual filtration values as the MGIV?

I'd have thought that there should be some slight differences but could these be so marginal that Ilford has either decided not to change the values or decided that it is something that can wait?

By the same token, it looks as if Ilford has decided that it has said enough about the changes in its comparison sheet to be able to rely on users to gauge the slight increase in time required when using filters 4 and 5. Thus it has not been worth its while to find out what the percentage increase is and include this in its leaflet

If anyone on Photrio has done the experiment with dual filtration then usually that person can't wait to inform all the others but so far I have seen nothing

In fact when I raised the point about not needing to double the exposure time for grades 4 and 5 with the new paper but any mention by Ilford as to what it's slight increase actually was this barely "rippled the water" and the best I go was agreement that my own working out what the percentage increase should now be, looked right but it would seem that no-one at that stage had bothered to test it and I have seen nothing more on it since

So these changes to MG5 v MGIV do seem to have been a bit of an non event for whatever reason

Mike
Reply With Quote
  #3  
Old 24th October 2021, 12:44 PM
Uwe Pilz's Avatar
Uwe Pilz Uwe Pilz is offline
Friend
 
Join Date: Dec 2020
Location: Leipzig, Germany.
Posts: 354
Default

My two Cents:

> exposure will remain the same (supposedly).

Which exposure should that be? That for the shadows? Or fo the highlights? Or the one for the 18% grey?

I found that for *single* filtration the time for the deep black (minimal time for maxima black) remains nearly unchanged. Actually, it changes only with the filter density, as it would be with non graded paper.
For me, this is a good starting point. I goof photograph should be a deep black somewhere, or it looks dull. For the first steps this rule is of worth for me.
The last steps, the last testing strips, are for fine adjustement and point to different regions of the image. But until I am here, I use this simple rule.
Reply With Quote
  #4  
Old 24th October 2021, 03:56 PM
John King John King is offline
Friend
 
Join Date: Nov 2012
Location: County Durham
Posts: 3,319
Default exposure

I think you have missed my point or I didn't explain it properly. Let me have another go.

Ignoring all other variables such as diffuser enlarger-V-condenser enlarger. Or even different light sources.

Say if you did test strips using the filter head from a colour enlarger at grade 2 which needed shall we say 20 seconds. Then you decided that there was not enough contrast, so upped the filtration to grade 3 in theory according to Ilford the exposure should be the same.

Now in the second scenario, you are using an enlarger with a non colour head condenser set up and have to use seperate filters for grade 2 and again you decide to 'up' the contrast and do another exposure at grade 3 in this case will the exposure be the same or will you have to do another test strip?

In other words does the statement by Ilford that the exposure will in theory remain the same when using seperate filters? Or are they only equal to single filtration?
Reply With Quote
  #5  
Old 24th October 2021, 04:16 PM
Mike O'Pray Mike O'Pray is offline
Friend
 
Join Date: Oct 2008
Location: Daventry, Northants
Posts: 8,969
Default

Quote:
Originally Posted by John King View Post
I think you have missed my point or I didn't explain it properly. Let me have another go.

Ignoring all other variables such as diffuser enlarger-V-condenser enlarger. Or even different light sources.

Say if you did test strips using the filter head from a colour enlarger at grade 2 which needed shall we say 20 seconds. Then you decided that there was not enough contrast, so upped the filtration to grade 3 in theory according to Ilford the exposure should be the same.

Now in the second scenario, you are using an enlarger with a non colour head condenser set up and have to use seperate filters for grade 2 and again you decide to 'up' the contrast and do another exposure at grade 3 in this case will the exposure be the same or will you have to do another test strip?

In other words does the statement by Ilford that the exposure will in theory remain the same when using seperate filters? Or are they only equal to single filtration?
I feel I may still not have understood you correctly, so,let me ask a few questions.

1. Is the comparison between colour head single filtration be that Y or M on the colour head dials and the Ilford separate under the lens 6 filters covering grades 0-5?

I think this is what you are saying but I'll stop here until you confirm this or otherwise to stop it getting confusing from the start

Thanks

Mike
Reply With Quote
  #6  
Old 25th October 2021, 12:01 PM
skellum's Avatar
skellum skellum is offline
Friend
 
Join Date: Dec 2011
Location: Isle of Lewis
Posts: 1,330
Default

Good afternoon John.

On a colour head: The dual yellow+magenta times are calculated in such a way that print exposure time remains the same for any and all grades.

Using the Ilford filters: Once you have an exposure time calculated for any one of the softer filters (00-3.5) you can change grades between them without retesting. But, if you go from soft to either G4 or G5 then double the time for the softer grade.

What I've never done is calculated an exposure time using the Ilford filters, then attempted to print on a colour head using the dichroic filters (or vice versa) for the same time.
I therefore can't say if the exposure time would simply transfer from one system to the other.
My feeling is that it won't work. If for example I had a print time of 15 seconds at G2 using the Ilford filters, but wanted to switch to G4 I'd have to make my print time 30 seconds.
However, on a colour head using dual filtration the print time would be the same. It implies that the dual filtration values are calculated to introduce a bit of (effectively) neutral density to keep print times the same. *

ps- The Ilford filters are prone to fading with use. I suspect your 'favourite' grades will fade faster than ones which rarely go under the enlarger lamp. There might then be a small exposure difference when you go from a well used to occasionally used filter. Couldn't quantify it, and my ancient filters are overdue for a change.
Dichroic filters apparently don't fade, so should be more consistent.

Hope I'm understanding your question here.

* Found this on data sheet. Confirms the single filter values give shorter times, but instead need recalculating when changing from grade to grade.
Dual colour filter settings
From the table below, read off the approximate
filtration needed for each contrast step. Dual
filtration values usually need longer exposure times
than single filtration values, but should need less
adjustment to exposure times when changing
contrast.

data sheet here: https://www.ilfordphoto.com/wp/wp-co...Multigrade.pdf

Last edited by skellum; 25th October 2021 at 12:08 PM. Reason: more info
Reply With Quote
  #7  
Old 25th October 2021, 12:48 PM
Terry S Terry S is offline
Friend
 
Join Date: Dec 2011
Location: Southend on Sea, Essex, England, UK
Posts: 3,797
Default

Personally, I have found over the years that if I change grade, I prefer to do a new test strip as the exposures used for under the lens filters do vary (although, maybe only slightly) between different grades.

I've never done a test of a negative, where it is printed using the same exposure for a range of grades of filter but I'm sure I've seen it done - in Ilford books / manuals? I must have a look. BUT, the only way to answer it, is for someone to do the test themselves. Having just read the following thread, it appears that results can vary between printers because of their different enlargers, lenses, light bulb used, age of their under the lens filters, the negative and it's contrast and of course the age of the paper used etc.

http://www.film-and-darkroom-user.or...read.php?t=845

It's worth reading the whole thread, as I have, but the following posts caught my eye:

Post #3 by Vincent:

I have found that if I changed my filter to above 3.5 and doubled up my exposure time, the result was unsatisfactory. My solution was to double up the time and do a test strip around that time.

Post #5 by Les McLean:

The best way to use filters is to make a test strip for each grade and forget about the guide in the manufacturers instructions. Yes, it will get you near to the correct exposure but not necessarily dead on the correct exposure which is where you need to be to produce the absolute best image from the paper.

Post #6 by Bob:

I tend to do a second test-strip at the new grade using, as suggested already, the theoretical new time as a guide only. It is often close, but rarely spot-on.

Post #10 by Martin Aislabie

Paper speed is matched for a mid-grey (0.6 density I think)

Which means the mid greys will match fairly well but the shadows and the highlights probably won't.

Post #14 by Richard @ RH Designs:

The "correct" exposure depends on the negative contrast as well, and I suspect Ilford's claim probably holds up if the negative contrast matches the paper contrast for each filter. If you print the same negative through a range of different filters with the same exposure then obviously the prints will look very different, and the harder grades will probably look "overexposed" due to the darkening of mid tones and blocking of shadows.

Consequently, a print that looks OK made at grade 2 with a certain exposure will almost certainly look too dark and therefore "overexposed" when printed at grade 4 with double the time. But the lightish mid-grey which represents the paper speed point will probably be unchanged - the exposure remains correct, it's the contrast that's wrong.

--------------------------------------------------------------------------------------------------------------------------

I hope the above posts are helpful, if you don't read the whole thread.

Terry S
Reply With Quote
  #8  
Old 25th October 2021, 01:27 PM
Tony Marlow Tony Marlow is offline
Friend
 
Join Date: Sep 2008
Posts: 1,282
Default

I am afraid this gets a bit too academic for me, when I change the settings I do a test strip to check with my eyes that it gives the result I want. Doing it this way I have never found an issue or confirmation that grades 4 and 5 need extra time. I am not sure that in practice it is necessary. Using the Dave Butcher method of split grade printing finding the correct exposure time at grade 2 1/2 then giving half this time at grade 0 and half at grade 5 gives the correct exposure time without any increase in the total time. I really think you need to make test strips and not rely on the theory.

Tony
Reply With Quote
  #9  
Old 25th October 2021, 01:43 PM
John King John King is offline
Friend
 
Join Date: Nov 2012
Location: County Durham
Posts: 3,319
Default

Forget it, I wish I had not asked!

Those that answered tried to help - thanks for that but then some introduced other variables which was not really what I was asking about. It is all getting too complex and way off the main question.
Reply With Quote
  #10  
Old 25th October 2021, 01:47 PM
skellum's Avatar
skellum skellum is offline
Friend
 
Join Date: Dec 2011
Location: Isle of Lewis
Posts: 1,330
Default

Sorry John.
Here is where the Internet Forum falls down.
If we could meet in the pub I reckon we'd have thrashed this out by about the fourth pint of Guinness.
Reply With Quote
Reply
Support our Sponsors, they keep FADU free:   AG Photographic   The Imaging Warehouse   Process Supplies   RH Designs   Second-hand Darkroom Supplies  

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Multigrade 5 Dave Hall Monochrome printing techniques 9 20th March 2020 02:10 PM
Multigrade Filters John King Darkroom 7 2nd February 2020 09:45 PM
Multigrade 500 Head PeterMcC Darkroom 2 23rd May 2016 07:25 PM
Multigrade dev photomi7ch Monochrome printing techniques 8 2nd June 2011 12:25 PM
The Other Multigrade Dave miller Chemical formulae 17 16th December 2008 09:05 PM


All times are GMT. The time now is 11:42 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.