contrast en brightness in colour enlarger

[game]

Hi,
Here I go again.
As i've explained in other topics: I know about b/w but I know shit about colour darkroom proces. For example:

On my durst m370 b/w enlarger there was a slot in which I could slide a peace of plastic in a orange tint with scales walking from 1 to 5 that could adjuct contrast. I don't see such a slot in my m605.

What the conclusion here?

> is it impossible to adjust contrast with a colour enlarger?

Thanks in advance - GAME

 

[gbroadbridge]

You adjust the Magenta and Yellow filtration using the following table as a starting point. Specifica papers may specify different filtration.

http://www.rhdesigns.co.uk/darkroom/html/junk1.html

graham

 

[Nick Zentena]

More yellow means softer [lower contrast] More magenta means harder [more contrast]

 

[game]

ok, I see. But does more yellow doesn't mean more yelow?
If you create an image with low contrast by adding yellow does that image not turn out to be yellower than it should be? And the same for magenta?

Thanks Game

 

[Nick Zentena]

Are you printing colour or B&W?

If you're printing colour negatives then more of a colour means less of the colour in the print. Adding yellow will mean less yellow in the print and more blue. But if you're printing colour then the information about changing contrast is wrong.

If you're printing B&W then all you get is black and white.

 

[jd callow]

If printing colour, which it appears you are, contrast control is achieved when shooting and or developing and is not attainable when enlarging. By going from a lower contrast paper (kodak portra, fuji CA 'P') to a higher contrast paper (Kodak supra, Ultima or their consumer line of papers or Fuji CA 'C') you can gain about a half to a whole increment in contrast.

It sounds as if you need to start at ground zero with your colour printing. Get a book on colour theory and or find a mentor. It is very easy, but difficult to do on your own.

 

[Ronald Moravec]

If your print has a yellow cast, add yellow. If blue, subtract yellow.

If it has a magenta cast, add magenta. If green subtract magenta.

If cyan, either add cyan or better subtract equal amounts of yellow and magenta. Red being the opposite of cyan, you add both yellow and magenta to correct escess red.

The problem is recognising these colors so you can make corrections. Cyan/blue are difficult to differentiate as are magenta/red.

Then they are combined errors such as a print having both a magenta and red cast.

Kodak used to make viewing filters so you view the print thru them. If it looked better thru the yellow filter, you knew it was a blue cast. If the various strengths of yellow did not fix it, you tried red as the cast is probably cyan.

 

[Ronald Moravec]

Now if you are doing black and white, just add some magenta if you need more contrast and additional time.

If you want to lower it, dial in some yellow and much less additional time, but some is required.

 

[roteague]

mrcallow's advice is right on, you don't adjust contrast in color materials the same way as you do in B&W.

 

[pentaxuser]

If your print has a yellow cast, add yellow. If blue, subtract yellow.

If it has a magenta cast, add magenta. If green subtract magenta.

If cyan, either add cyan or better subtract equal amounts of yellow and magenta. Red being the opposite of cyan, you add both yellow and magenta to correct escess red.

The problem is recognising these colors so you can make corrections. Cyan/blue are difficult to differentiate as are magenta/red.

Then they are combined errors such as a print having both a magenta and red cast.

Kodak used to make viewing filters so you view the print thru them. If it looked better thru the yellow filter, you knew it was a blue cast. If the various strengths of yellow did not fix it, you tried red as the cast is probably cyan.

Game. This is really a reply to you but I am using this reply as the quote as it mentions Kodak Viewing filters. I obtained a set from the person from whom I bought my JOBO for colour printing. I found them inadequate to help me correct a cast and eventually gave up trying to correct this way. Kodak recommend a certain starting level of Y and M. Look up its website for RA4 paper for the exact recommendation. Fuji doesn't seem to give a recommendation for its paper but it isn't that different.However this person also sold me a set of test negs and prints which represent the ideal from which I was able to eventually replicate the print. Once I had the correct Y and M levels in my dichroic head I was able to calibrate my colour analyser to produce good prints from any negs OF THE SAME FILM TYPE ON THE SAME RA4 PAPER. Different films such as Fuji, Konica and Kodak will all have different correct calibrations based on either Fuji or Kodak paper.

In theory once you establish the correct Yand M settings for a particular film type and paper then all all the other negs should be acceptable at this setting. My experience has been that while this is true of most negs on a roll of film, the setting can vary sufficiently to make the purchase of an analyser worthwhile. The alternative is being prepared to waste more paperby running test prints and trying new combinations of Y and M every time that a particular print doesn't work with the dichroic settings.

An alternative to test negs and prints from a manufacturer such as Fuji is to get a colour neg film developed and printed professionally then try and replicate that print and once you have succeeded, use those settings.

If my experience is anything to go by,you will have to be prepared to waste quite a lot of paper and be patient. Keep notes on Y&M settings and exposure as you go along.The first B&W print I ever did was far more acceptable than the first colour print, although once I had succeeded I now find that colour printing is more mechanical and in that sense more straightforward than producing good B&W prints.

Best of luck

Pentaxuser

 

[game]

Hmmm, I understand now.
You guys are right. As it comes to colour I'm worth nothing. But I'm learning. When all is set up and running I will talk to some sort of mentor guy I know.
I just have the feeling that you can control more than just saturation and colours when doing colour prints. Am I right about that?

Thanks for replying, Game

 

[Mick Fagan]

Colour and saturation are pretty much all you can control in colour printing!

If you deviate from the normal processing procedures, you will invariably get wrong colour, diluted colour, colour cross over and a multitude of other sins.

That said, there is nothing wrong with experimenting in time,temp and agitation, as well as different colour filtration to get some unreal effects.

However I think you should first learn, correct colour printing before you start deviating. Fancy equipment is not a necessity, although all beginners think it will help them, I know I did and all other people that've taught colour printing thought the same.

I myself have gone through all sorts of density probes, colour analysers but these days I rarely use any of them. These days when I go into the darkroom for colour printing, I can invariably get a session going with using one 8x10" piece of paper for density and colour correction.

If you are going to go the colour analyser route, find someone with a Jobo Colorstar and get them to show you how it works. The Jobo is the only one that I know of, that measures all three colours at once. The three colours it measures are yellow and magenta for the two main colours and cyan for density, which controls red. It's all done in one go and is the easiest analyser I've ever used, out of the 10 or so different analysers I've experienced.

When you start colour printing it is a nightmare, no matter what you do it seems impossible to get a correct colour. One day it all snaps together and you'll be sweet. Most colour printers I have met say the same thing.

The colour viewing filters from Kodak, are a very helpful tool in choosing exactly what kind of colour cast (if any) that you have. You really need to learn how to use them. Also, as far as colour casts are concerned, I have found that women are far better in discerning if there is a cast and also seem to have a better idea of just what cast it is.

For quite some time, when I was teaching myself colour printing, I would bring a set of prints in from the darkroom and the missus would invariably say, "they are too blue", or something like that. It did infuriate me, mainly because I considered them to be accurate. Come the next day, another look and yep she was right. Gradually you understand the subtle differences.

Eventually I started working in an industrial colour lab where we specialised in printing colour murals and when you are doing single piece colour prints that are 6' high by 18' long you need to get correct colour. Basically whoever was working on a mural print would do one or two 3'x3' prints from various sections of the enlargement, to get close to colour and density.

Then another test print would be done and it would sit on the floor of the lab for perusal and discussion. The discussion would be by at least three and up to five people, as to what they thought it needed to get it right. Decisions were finalised and then a print would be made. Usually we got it right, very occassionally we got it wrong.

Looking forward to finding out how you get along.

Mick.

 

[Ed Sukach]

Colour and saturation are pretty much all you can control in colour printing!

Contrast CAN be controlled in color printing by pre-flashing - Exposing the paper intially to an overall color-corrected gray for 10% - 20% of the total exposure. Harder to describe than do - but *very* effective in reducing (only) excessive contrast.

If you are going to go the colour analyser route, find someone with a Jobo Colorstar and get them to show you how it works. The Jobo is the only one that I know of, that measures all three colours at once. The three colours it measures are yellow and magenta for the two main colours and cyan for density, which controls red....

I'm having trouble trying to understand the "...cyan for density, which controls red" ...?
When analyzing, the ColorStar 3000 (? - Is there a difference with other models?) will display four quantative values: Magenta, Yellow, Cyan, and Density. I think there is an internal processing system that combines M,Y, and C to obtain Density ... but density doesn't "control" red ... or am I missing something?

 

[roteague]

Don't forget, you can still do the traditional dodging and burning.

You can also control contast by doing contast masking as Christopher Burkett does with his Ilfochrome prints - difficult, but it works well.

 

[jd callow]

by adding equal parts YM and C you reduce the light passed through the neg. Equal parts of all 3 filters creates a ND filter equal to the quantity in CC added.

Cyan by its self only increases cyan, and therefore cause the print to print more red.

 

[pentaxuser]

Contrast CAN be controlled in color printing by pre-flashing - Exposing the paper intially to an overall color-corrected gray for 10% - 20% of the total exposure. Harder to describe than do - but *very* effective in reducing (only) excessive contrast.


I'm having trouble trying to understand the "...cyan for density, which controls red" ...?
When analyzing, the ColorStar 3000 (? - Is there a difference with other models?) will display four quantative values: Magenta, Yellow, Cyan, and Density. I think there is an internal processing system that combines M,Y, and C to obtain Density ... but density doesn't "control" red ... or am I missing something?

Ed. This sounds like a very useful tip. How does one obtain a colour corrected grey. Is this ND by dialling in equal amounts of YM&C? If so how does one decide how much? Is it all trial and error or is there a way of getting at least close to the right amount of colour corrected grey.

Thanks

Pentaxuser

 

[antonius]

Hi,
Here I go again.
As i've explained in other topics: I know about b/w but I know shit about colour darkroom proces. For example:

On my durst m370 b/w enlarger there was a slot in which I could slide a peace of plastic in a orange tint with scales walking from 1 to 5 that could adjuct contrast. I don't see such a slot in my m605.

What the conclusion here?

> is it impossible to adjust contrast with a colour enlarger?

Thanks in advance - GAME

Do you want to adjust contrast for making a colour print or a monochrome print?

 

[Mick Fagan]

Ed, you are correct about the pre flashing to control excess contrast. Another thing I should have thought about, before putting fingers to the keyboard.

I would assume that there is a difference between Colorstar models. I myself have the original Colorstar, prior to that my main unit for many years was a Beseler which had insertable modules for different papers and/or film combinations. It also came with a fantastic little handbook, which I passed on when I sold it for the Jobo. One of the best pieces of advice I found in that little book, was this:-

“The most common source of filtration problems are prints that are too dark. A heavily exposed test print will usually look red. Then chasing our tails, we attempt to correct the exposure and balance simultaneously. When exposure is decreased, the amount of red diminishes by itself. So there is a built in tendency to overcorrect the second print.”

I pondered this paragraph in that book, for quite some time. Eventually I woke up to the fact that there are three colours in the film and three in the enlarger head. We actually use all three colours when enlarging, the Yellow & Magenta filters are the ones we adjust on the enlarger head, Cyan is controlled by the density, which is a time adjustment.

The only time before that revelation I had used cyan, was when I needed neutral density to slow down printing times when making extremely small prints.

Mick.

 

[Ed Sukach]

Ed. This sounds like a very useful tip. How does one obtain a colour corrected grey. Is this ND by dialling in equal amounts of YM&C? If so how does one decide how much? Is it all trial and error or is there a way of getting at least close to the right amount of colour corrected grey.

To correct color contrast by "pre-flashing", expose a sheet of paper to a color negative of an 18% grey card for a fraction of te total exposure time. Place the grey negative in the carrier and adjust Magenta, Yellow, and Cyan filtration to null out the ColorStar. The Colorstar will indicate an exposure time required to make a "neutral" density image (.053, in ColorStar units). Expose the paper for 10% to 20% of that time. Then, remove the paper, insert the negative to be printed in the carrier and analyze that one for the proper color balance and exposure time. Expose the "real" negative on the pre-flashed paper for the remainder of the time; e.g., for a 20% pre-flash, expose the paper to the balanced grey card image, where the indicated time is 10 seconds, for 2 seconds (20% of 10 seconds); and complete the exposure by exposing the "real" image for the remainder of the indicated time - if the second time indicated was 20 seconds, the final exposure will be for 16 seconds, (80% of 20 seconds).

Much easier to do than explain. Even easier to show than tell.

This once saved my rear end .. I had photographed a group of girls wearing white evening gowns (primarily satin) on the front steps of a College building ( complete with white Corinthian columns) in bright, direct noonday July sunlight. A straight color print had severely - totally - black and featureless shadows and equally totally featureless whites. With a 20% pre-flash,... miracle upon miracles ... shadow detail AND texture in the white satins!

 

[Ed Sukach]

I pondered this paragraph in that book, for quite some time. Eventually I woke up to the fact that there are three colours in the film and three in the enlarger head. We actually use all three colours when enlarging, the Yellow & Magenta filters are the ones we adjust on the enlarger head, Cyan is controlled by the density, which is a time adjustment.
The only time before that revelation I had used cyan, was when I needed neutral density to slow down printing times when making extremely small prints.

Not quite.

Color paper and color film BOTh have three layers - one sensitive to Magenta, one to Yellow, and one to Cyan (I'll exclude Fuji, for the moment). To print color properly, each layer must be exposed to obtain the proper density. The final, overall density will be a total of all the light-sensitive layers. If we add additional light to any individual layer, we will bias the final image in that direction. To only add cyan, for example, will increase the amount of yellow in the print (remember, we are working with a negative). To re-balance the final image, it is necessary to add more yellow and magenta to compensate, and the final image will then have the proper color balance, and the desired increased overall density.

Modern color negative films have a built-in (negative) cyan bias, observed as a dark yellow (a.k.a. "brown") cast, to eliminate much of the need for cyan filtration. In balancing, Magenta and Yellow are the only filtration usually necessary to "catch up" to the Cyan bias.

There are occasions where the "pre-cyan" bias is not enough, and cyan must be added to obtain balance. As an example, I have worked with a technique where images of color slides are projected onto the bodies of models, and the whole thing was captured on daylight-balanced film. First, the lamp in the
projector has a spectrum much lower in color temperature than daylight - something like 3600K as opposed to 5500K daylight - and all bets are off anyway, after the light passes through the color transparency.

In printing, those images took a lot of magenta, yellow AND cyan filtration to obtain skin tones that actually looked like skin. I think that printing those would have been nearly impossible without the ColorStar.
See "Floral Nude #1" and "Floral Nude #2" in my gallery.

 

[game]

Don't forget, you can still do the traditional dodging and burning.

can someone explain this?

 

[pentaxuser]

Ed Thanks. I have a Paterson analyser with which you have to null Y,M and C separately but everything you have said should be translatable to my analyser.

Pentaxuser

 

[Ed Sukach]

Ed Thanks. I have a Paterson analyser with which you have to null Y,M and C separately but everything you have said should be translatable to my analyser.
Pentaxuser

De nada!

I wish this could be truly cut and dried, but I suspect there will be *some* trial and error.

I tried to teach this to a couple of my "mentorees". Not easy to explain WHY this reduces contrast, but it does - very effectively.

If I can help in any way, do not hesitate to let me know.