I question regarding paper developer temperature and contrast

[Mainecoonmaniac]

I ordered an RH designs Analyzer Pro and I'm slowly calibrating it. It requires me to run test prints to calculate the sensitivity of the paper. It's done with a 7 step progressive test strip. The goal is to find a light gray with the reflected density of .04. The calibration worked when the paper developer was 70° F. California is in a middle of a heat wave and my darkroom is not air conditioned. When I used the analyzer when the developer temperature was 85°, my targeted pale gray was now way lighter. It looks like for me to work with the analyzer, I have to keep the paper developer around 70°.

I'm sure this was asked on Photrio before, what does warm paper developer do to photographic paper. BTW, I'm using Ilford Multigrade IV and home brewed Ansco 135 paper developer.

Does anybody have experience with calibrating the RH Analyzer Pro? So far, it's an awesome piece of darkroom gear But user error (warm developer) us causing me headaches.

 

[revdoc]

How long are you developing? Are you getting to finality?

Also, did you use a regulated power supply for the exposure? Line voltages can vary, which can change your exposure noticeably.

 

[RalphLambrecht]

I ordered an RH designs Analyzer Pro and I'm slowly calibrating it. It requires me to run test prints to calculate the sensitivity of the paper. It's done with a 7 step progressive test strip. The goal is to find a light gray with the reflected density of .04. The calibration worked when the paper developer was 70° F. California is in a middle of a heat wave and my darkroom is not air conditioned. When I used the analyzer when the developer temperature was 85°, my targeted pale gray was now way lighter. It looks like for me to work with the analyzer, I have to keep the paper developer around 70°.

I'm sure this was asked on Photrio before, what does warm paper developer do to photographic paper. BTW, I'm using Ilford Multigrade IV and home brewed Ansco 135 paper developer.

Does anybody have experience with calibrating the RH Analyzer Pro? So far, it's an awesome piece of darkroom gear But user error (warm developer) us causing me headaches.

dev time has an influence on contrast: the longer the more contrast; a cooler dev increases dev time; ergo: the cooler the more contrast.

 

[138S]

I'm sure this was asked on Photrio before, what does warm paper developer do to photographic paper.

A "weak" developer (or a regular developer nearing exhaustion) is unable to fully reduce the silver halide in the emulsion, shifting it to warm tone. A warm paper contains halides that are more difficult to reduce, and a warm tone developer is weak enough make it more difficult to totally reduce the silver halide. Cold vs Warm is about chemical reduction (contrary to oxydation):

> Totally reduced is cold tone
> Not well reduced is warm
> Something in the middle is neutral

If you add bromide then reduction is lower because the chemical equilibrium tends to reduce less, and you get a warmer result.

Just consider that the severity of the chemical reduction depends on if the halides in the paper are more/less dificult to reduce, and on the developer's capability to reduce more/less, adding bromide you reduce less.

Some developers like Ansco 120 (Glycin) are suitable to modify tone a bit by adjusting chemical exhaustion, the more exhausted the warmer, fresh and used developer can be mixed to adjust warmth. With other developers it is more difficult to adjust exhaustion in an stable way, but you also adjust tone in a way or other. IMO a sound work may end with some selenium or the like, you do the job there.

The degree of development depends on time and on temperature, one thing can be traded by the other. Not developing to completion may slightly change a bit the warm/cold tone and contrast. ...but as Ralph pointed things are not always linear and some extended time may allow some additional crystals to develop increasing contrast.

I my targeted pale gray was now way lighter. It looks like for me to work with the analyzer, I have to keep the paper developer around 70°.

Let me mention another potential factor weakening the highlights

Also exposure time on paper has an impact.

Let's imagine we have a correct exposure at 20s. Then we decide close diafragm by 2 additional stops. Well, our new time will be 80 seconds, isn't it ? This exposure will be mostly correct for the shadows (in the scene) than throw a lot of light on paper, but our highlights (scene) ara very dense in the negative and of "low intensity": We may have Low Intensity Reciprocity Failure specially in our highlights, delivering a lighter grey, and increasing the perceived contrast.

This not only happens when stopping more the lens... if you rise the enlarger's head to print to the double size you have x4 the area so time has to be compensated by an x4 factor longer, again that corrected exposure will be not perfect for the highlights receiving low intensity and also at risk of having LIRF. For this reason when crafting an smaller prototype to later make a big print the lens may be stoped to deliver the same illumination than when making the big print, for example, if we are to make the big print at f/5.6 then a prototype thar has half the size should be made at f/11, in that way the big print will receive the same light intensity than the smal print, we won't require a time correction, and the highlights will be equal than in the prototype.


So, like with film, reciprocity failure is well higher in the areas receiving a lower intensity... An equivalent but longer exposure relatively weakens more the (scene) highlights.

 

[Ian Grant]

85ºF (29.4ºC) is too high for papers the chances are you'll have base fogging, also development times would need to be very short if 2 mins at 20ºC then 25 to 30 seconds at this high a temperature.

Unlike films which aren't developed to a high Dmax papers are different and designed to give an optimal tonal range at a range of development times and with no Contrast shift to quote Ilford "Development can be extended up to 6 minutes without any noticeable change in contrast or fog." that's assuming you develop for their minimum recommended time or longer.

Ian

 

[Mainecoonmaniac]

How long are you developing? Are you getting to finality?

Also, did you use a regulated power supply for the exposure? Line voltages can vary, which can change your exposure noticeably.

I really don't know about the line voltage, but I'm sure there are fluctuations with the power because people were running their air conditioners. I'm using a Beseler Dichro 45S head. I don't know if the internal supply is stabilized or not.

I'm developing about 1 1/2 minutes.

 

[Mainecoonmaniac]

dev time has an influence on contrast: the longer the more contrast; a cooler dev increases dev time; ergo: the cooler the more contrast.

Hi Ralph. Thank for the information. I was hoping the RH Analyzer Pro calibrated at 70° developer temperture would get me in the ball park with the 80° developer. The targeted density of .04 isn't even close. But I'm still learning. I've been printing for over 30 years and never used an analyzer in an environment where the temperature of the chemistry was not tightly controlled.

 

[Mainecoonmaniac]

A "weak" developer (or a regular developer nearing exhaustion) is unable to fully reduce the silver halide in the emulsion, shifting it to warm tone. A warm paper contains halides that are more difficult to reduce, and a warm tone developer is weak enough make it more difficult to totally reduce the silver halide. Cold vs Warm is about chemical reduction (contrary to oxydation):

> Totally reduced is cold tone
> Not well reduced is warm
> Something in the middle is neutral

If you add bromide then reduction is lower because the chemical equilibrium tends to reduce less, and you get a warmer result.

Just consider that the severity of the chemical reduction depends on if the halides in the paper are more/less dificult to reduce, and on the developer's capability to reduce more/less, adding bromide you reduce less.

Some developers like Ansco 120 (Glycin) are suitable to modify tone a bit by adjusting chemical exhaustion, the more exhausted the warmer, fresh and used developer can be mixed to adjust warmth. With other developers it is more difficult to adjust exhaustion in an stable way, but you also adjust tone in a way or other. IMO a sound work may end with some selenium or the like, you do the job there.

The degree of development depends on time and on temperature, one thing can be traded by the other. Not developing to completion may slightly change a bit the warm/cold tone and contrast. ...but as Ralph pointed things are not always linear and some extended time may allow some additional crystals to develop increasing contrast.



Let me mention another potential factor weakening the highlights

Also exposure time on paper has an impact.

Let's imagine we have a correct exposure at 20s. Then we decide close diafragm by 2 additional stops. Well, our new time will be 80 seconds, isn't it ? This exposure will be mostly correct for the shadows (in the scene) than throw a lot of light on paper, but our highlights (scene) ara very dense in the negative and of "low intensity": We may have Low Intensity Reciprocity Failure specially in our highlights, delivering a lighter grey, and increasing the perceived contrast.

This not only happens when stopping more the lens... if you rise the enlarger's head to print to the double size you have x4 the area so time has to be compensated by an x4 factor longer, again that corrected exposure will be not perfect for the highlights receiving low intensity and also at risk of having LIRF. For this reason when crafting an smaller prototype to later make a big print the lens may be stoped to deliver the same illumination than when making the big print, for example, if we are to make the big print at f/5.6 then a prototype thar has half the size should be made at f/11, in that way the big print will receive the same light intensity than the smal print, we won't require a time correction, and the highlights will be equal than in the prototype.


So, like with film, reciprocity failure is well higher in the areas receiving a lower intensity... An equivalent but longer exposure relatively weakens more the (scene) highlights.

Thanks for the information. Obviously, I still have a lot to learn about subtleties what effect highlights. I was hoping the the analyzer would help me calculate my exposure without test strips.

 

[Ian Grant]

Hi Ralph. Thank for the information. I was hoping the RH Analyzer Pro calibrated at 70° developer temperture would get me in the ball park with the 80° developer. The targeted density of .04 isn't even close. But I'm still learning. I've been printing for over 30 years and never used an analyzer in an environment where the temperature of the chemistry was not tightly controlled.

Ralph's information was incorrect, go read an Ilford datasheet, extending development does not increase print contrast, if anything it actually reduces it as highlights and mid tones develop more after the shadows have reached D max.

Ian

 

[Mainecoonmaniac]

Ralph's information was incorrect, go read an Ilford datasheet, extending development does not increase print contrast, if anything it actually reduces it as highlights and mid tones develop more after the shadows have reached D max.

Ian

Thanks Ian. Does reducing highlights and mid tones mean a shift towards darker tones?

 

[138S]

I was hoping the the analyzer would help me calculate my exposure without test strips.

It is difficult to totally avoid test strips... but you may reduce the amount you make.

You may use the analyzer to first get the exposure for the highlights, and with that exposure use the analyzer just find the grade that delivers the shadow density you want.

As always, a negative containing a large dynamic range may not fit in the paper and some manipulation may be required.

You may also try split grade, with split grade you end anyway in particular grade, but you adjust the print in a different way. You adjust the Grade 00 exposure alone to have the highlights you want, later you adjust the the Grade 5 exposure alone to have the the shadows you want, as you expose both (the 00 and the 5 grade exposures) you have your print.

Split grade allows to dodge selectively in one or the other exposure.

 

[Ian Grant]

Thanks Ian. Does reducing highlights and mid tones mean a shift towards darker tones?

A muddier print, less subtle. It depends on the paper.

Ian

 

[radiant]

Ralph's information was incorrect, go read an Ilford datasheet, extending development does not increase print contrast, if anything it actually reduces it as highlights and mid tones develop more after the shadows have reached D max.

Ian

This is what I have thought too.

Borut Peterlin explained in one video that when he mixes new paper developer he adds some "old" developer it because it fresh developer is too harsh in his words. I don't know if he is developing to dMax but I would guess. But then I don't understand his mixing idea.

Actually here is the video and the part (start at 7:00)

 

[MattKing]

Adding old developer might make the results more consistent over the life of the developer in the tray, particularly if you also replenish throughout a long printing session.

 

[Ian Grant]

Adding a bit of older developer will increase the Bromide level, that's essentially a developer starter in what's going to be a replenished system. A Warmtone developer gets warmer with use due to the Bromide build up. Personally I don't do this and still have the same control of the image colour with my Warmtone papers.

With a Bromide paper you should develop to achieve Dmax and usually a fraction more. With Warmtone papers you developer for the desired warmth which is image tone colour.

Ian

 

[Mainecoonmaniac]

With the RH Analyzer Pro, the exposure is set with a highlight of a pale gray where the reflected reading is .04. With 85° developer, it was whiter. Could the test print's highlight become more pale as the developer gets warmer? Or the only way a highlight density could become less is with less exposure?

 

[Ian Grant]

At that temperature you may well be giving less exposure. But increasing temperature will darken the highlights slightly.

Ilford make (or made) some special papers for High temperature and speed processing (I have some long rolls) so know the data sheets.

This is for Ilford Multigrad Xpress RC
Temperature Development time (sec) (°C/ºF) including transfer time to next tank

20ºC/68ºF 46 seconds
25ºC/77ºF 32 seconds
30ºC/86ºF 22 seconds
35ºC/95ºF 15 seconds
40ºC/104ºF 12 seconds

These times are for replenished developer designed for high temperatures which most of their papers aren't.

Ian

 

[Mainecoonmaniac]

At that temperature you may well be giving less exposure. But increasing temperature will darken the highlights slightly.

Hi Ian,

Thanks for the very useful information.

Cheers!
Don

 

[Pieter12]

I know an excellent (professional) printer who swears by developing at 80º--he says it gives him denser blacks. And his prints are certainly not muddy or flat. Another professional printer I know develops Ilford MGFB for 7 minutes to get deep blacks.

 

[Pieter12]

Temperature greatly affects the operation of equipment. Usually after 50 degrees there are problems and the result may be undesirable.

We are talking Fahrenheit, correct?

 

[Pieter12]

We are talking Fahrenheit, correct?

yes

There's not much equipment that could be affected making black and white prints.

 

[pentaxuser]

Temperature greatly affects the operation of equipment. Usually after 50 degrees there are problems and the result may be undesirable.

So a temperature in excess of 50 degrees Fahrenheit greatly affects equipment and has an undesirable result ? Can you say what equipment and what these undesirable results might be?

Thanks

pentaxuser

 

[DREW WILEY]

Out of bounds temps tend make certain dev ingredients behave differently in relation to other ingredients than they were intended to do around std room temp of 20C. This affects not only contrast but final image color, and esp how the different emulsions in a VC paper might come out relative to one another. Can't you set up a cooler water jacket around the dev tray, containing a cold water drip line or Blue Ice pack? Don't confuse RC specs potentially related to automated roller transport processors with how fiber based paper is going to perform in an ordinary tray.

 

[RalphLambrecht]

Ralph's information was incorrect, go read an Ilford datasheet, extending development does not increase print contrast, if anything it actually reduces it as highlights and mid-tones develop more after the shadows have reached D max.

Ian

the midtone portion of the curve becomes steeper with increased development, which means increased contrast to me

 

[Ian Grant]

You are actually reducing the contrast in the shadow areas and also the difference between the mid tones and the Dmax, the consequence is loss of detail in the mid tone to shadow areas.

Ian