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  #1  
Old 27th February 2016, 01:28 PM
cesare cesare is offline
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Default Well, i've finally order some colour paper...

Since i've got a colour enlarger, and a fair bit of colour film to my name, I thought it was time I actually had a go at making some colour prints. I've got some more C41 on order, but this time i've also picked up some RA4 and colour paper...

So, for a reasonably experienced B&W printer, what pitfalls should a novice discover in the world of colour printing?

Equipment wise, i've got a Jobo rotary processor which does my C41 processing, and armed with some paper tanks and RA4 chemistry, it should also be able to process colour paper.

I've got a colour analyser somewhere, a simple 'tell you if it needs more magenta' type affair, so i'm guessing I can use this on my easel and adjust the colour head to work out a white point.

I presume I have little contrast control beyond the behaviour of my paper, so i'm guessing it's going to be about white point, overall density, and any dodging to keep the density in check.

I presume there is no 'reversal' technique for chromes?

Any advice appreciated, i'll post my first attempts when I get things going (probably a week before the chemicals arrive).
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Old 27th February 2016, 02:27 PM
Mike O'Pray Mike O'Pray is offline
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Cesare,I take it that this is Fuji paper but whatever it is, it will help if you can name it. Once this is known then the RA4 users here can tailor the advice to that paper.

Mike
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Old 27th February 2016, 04:15 PM
cesare cesare is offline
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Originally Posted by Mike O'Pray View Post
Cesare,I take it that this is Fuji paper but whatever it is, it will help if you can name it. Once this is known then the RA4 users here can tailor the advice to that paper.

Mike
Good point. It's listed as 'Fuji Crystal Archive photographic color paper matt 7x9.5" (17.8x24cm)'
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Old 27th February 2016, 06:12 PM
JOReynolds JOReynolds is offline
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Originally Posted by cesare View Post
I presume there is no 'reversal' technique for chromes?
Once upon a time there were reversal papers, manufactured by Kodak Pathé, that used the R14 process. The stop bath was replaced by a water bath and a few other changes and it became process R3. If the transparency was correctly exposed and the lighting was fairly flat the results could be excellent. I don't know if there are any published formulae but it might be worth experimenting with reversal-processed RA4 paper.
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Old 27th February 2016, 06:53 PM
Mike O'Pray Mike O'Pray is offline
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Thanks. The reason the paper type is important is that the starting Y and M filtration needed to get within the "ball park" of the right neutral colour balance is different for Fuji v Kodak

The other factor is how your analyser works. With most analysers you need to use a neg with a good balance of colours and having flesh tones and if possible a mid-grey section.

You then usually need to produce "the perfect print" from that neg and then use the "correct" Y and M settings on the colour head to calibrate the analyser. Once calibrated it will then give you the Y and M settings for all other negs you develop.

Producing the perfect print has to be done without any mechanical help so to speak so a neg with a know mid-grey area and a good flesh tone helps a lot as you will see any colour cast in those areas most easily.

Have you got access to a colour correction chart? That's essential. There might be one with the Fuji paper but all colour printing chapter/ books will have one.

The first thing you need to do is get close to the right exposure. A Paterson test strip printer is useful here. Cut a 4x5 from one of your sheets and give it 5 different exposures at 1 sec intervals starting at say 3 secs. This might get you close. If not use a second piece

You can usually tell which is the best exposure even if there is a colour cast.

Once you have the right exposure I'd use a second sheet and cover 3 parts, expose the first with the ball park Y and M then increase the the Y and M settings by say 5 each, then decrease the settings by 5 each. You need to know the time factors involved when you change the settings. Changing M will increase or decrease exposure.

Keep notes on everything you do so you know what the changes were for each section

If you haven't already done so it is worth getting a book on colour print processing.

Don't expect to walk out with even a good colour print after an hour or so. Really getting the feel for colour adjustment might take a few sessions. In my experience patience is called for, I am afraid.

Mike
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Old 28th February 2016, 01:25 PM
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GoodOldNorm GoodOldNorm is offline
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I would suggest that you take a photograph of a mixed display of colour objects, fill at least 1/5th of the frame with a white textured towel and at least 1/5th of the frame with a mid grey, also include a flesh tone. The rest can be made up of a colour chart or a paint pallet, colour pencils, grass, blue sky etc.
The negative will give you a print that will be easy to see colour cast especially on the white object, aim for getting the grey correct with no hint of colour cast on the white and you will be very close.

Use changes of 15 or 20 filter units to start with it is easier to see the changes of colour cast ,you can fine tune using 5 units of filtration as you get close to your correct print.

I do not use an analyser, I dry the print with a hairdryer and the look at it in daylight or under a blue daylight bulb.

Once you get the knack I think colour printing is easier that black and white, good luck with your endevours.
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Old 29th February 2016, 12:49 PM
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Do not look at the test under the 'Energy-Saving' light bulbs as they give out too much Magenta and the result under 'daylight' will be a Green cast !
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Old 29th February 2016, 02:01 PM
Mike O'Pray Mike O'Pray is offline
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Do not look at the test under the 'Energy-Saving' light bulbs as they give out too much Magenta and the result under 'daylight' will be a Green cast !
Is daylight so-called "daylight" energy saving bulbs or daylight as in light of the sun? If its the latter then what's a "true" light under which to view a print, Pete?

If daylight is normal light from the sun then how do you ensure that a RA4 print looks correct in both daylight and night-light which I take it to be incandescent light.

It raises interesting questions given that soon there will only be energy saving bulbs in houses or perhaps only a little further into the future only LED bulbs

Mike
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Old 29th February 2016, 04:51 PM
JOReynolds JOReynolds is offline
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Default Optimum viewing lightsources

Quote:
Originally Posted by Mike O'Pray View Post
If daylight is normal light from the sun then how do you ensure that a RA4 print looks correct in both daylight and night-light which I take it to be incandescent light.
The problem is that most efforts at simulating daylight emit a discontinuous spectrum, which the eye, after adaptation, perceives as neutral but is actually made of peaks and troughs, to which different dyes respond differently. The dyes in colour paper are intended to look good under a variety of lightsources. 'Colour matching' fluorescent tubes give the best rendering currently available. The document below singles out Matsushita's tubes for praise. But that was thirty years ago. Luminaires housing such tubes often include an hour-meter because the accuracy of rendition depends on a blend of phosphors that fade at different rates. A typical lifespan is given as 1000 hours.
A thorough explanation of rendering and metamerism is presented in:
National Gallery Technical Bulletin Volume 9, 1985, Colour Under Some New Fluorescent Lamps.
ISBN 0901791 97 0
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Old 18th March 2016, 06:31 PM
cesare cesare is offline
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Ok, chemistry turned up, and paper. I had a quick play last night, mixed up some chemistry, and ran three prints. First, totally black, second, light and mainly orange, third, too dense, but it's got colour, and although it won't win any awards, it is a print!

So, this weekend, i'll get the analyser out, and get my old jobo processor out of the loft (a CPE2) which will be perfect for keeping the chemistry suitably tempered - last nights effort was bottles in a sink, and i'm sure things will have drifted cold whilst I was fiddling.

Lots to do and discover, now to dig through my old colour negs...
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