Digital Negatives

[ian barber]

I have started to build a Photoshop Plugin for calculating the correction curve for darkroom papers when using digital negatives.
Very early days in development but here is a result from the first auto correction curve produced from the program.

The grey ramp clearly indicates I have some way to go in order to achieve better separation.


The grey ramp

 

[Toby Webster]

This is interesting, Ian. You must have the patience of Job.

It will be interesting to see if you get consistent results from one digital frame to another.

 

[ian barber]

In theory, once you have established the base exposure time for the paper, the results should be quite concistent.
I started out using the enlarger white light but currently, I am just using a 7w bulb hung above the paper which is giving good results.

For Ilford MG Pearl, the base exposure is around 15 seconds ussing the bulb

 

[Glenn]

In theory, once you have established the base exposure time for the paper, the results should be quite concistent.
I started out using the enlarger white light but currently, I am just using a 7w bulb hung above the paper which is giving good results.

For Ilford MG Pearl, the base exposure is around 15 seconds ussing the bulb

Interesting. I guess, in a way, it is analogous to large format contact printing which takes out any optical imperfections of the enlarger and its lens.

So is the idea to replicate the linearity of a digital print on photographic paper or will you allow for the inherent non-linearity of the film negative-positive process to give a filmic look to your final print?

 

[ian barber]

Interesting. I guess, in a way, it is analogous to large format contact printing which takes out any optical imperfections of the enlarger and its lens.

So is the idea to replicate the linearity of a digital print on photographic paper or will you allow for the inherent non-linearity of the film negative-positive process to give a filmic look to your final print?

Over the past 8 years or so, it has become quite popular and people are using the method for all kinds of alternative process like platinum, cynotype etc.

For me the interest was been able to contact a 5x4 negative to what size you want.

Regarding the linearity, because we are printing onto a film type substrate as a negative, by nature when the ink is dry is has a non linear result but we have to do more.

We have to be able to control the density in such a way that we dont wind up blocking the low or high values which we do by making a correction curve based upon how the darkrom paper reacts to the density of the digital negative.

 

[Glenn]

Got it. Thanks.

 

[ian barber]

So the workflow goes sometihng like this...

• Take a photograph using traditional film
• Develop and scan it
• Edit it using your editing software
• Create a correction curve for the darkroom paper
• Print it onto Inkjet film, I was using Pictorico
• Contact print it in the darkroom either using the enlarger white light or a 7w bulb hung above the paper

Correction Curve For Ilford Grade 2 Paper



Contact printed onto Ilford Grade 2 Paper

 

[Glenn]

If you have the enlarger set up, it might be interesting to see a side-by-side comparison of a print made with the digital negative workflow and a traditional wet-process enlargement.