Understanding Split Grade Printing

[cliveh]

Well I have met digital photographers who are more concerned in getting the histogram curves as they want them, without looking at the image.

 

[MattKing]

OK. Lead me through how you would use this information to make a split-grade print.

I've mentioned this before. If you want to understand/visualize how variable contrast paper does what it does, create a good quality, straight (no burning or dodging) split grade print of a fairly normal scene - one that, as usual, involves one exposure of the low contrast green light/yellow filtered light and another exposure of the high contrast blue light/magenta filtered light. Take note of those two exposure times.
Now do separate prints - one with just the low contrast green light/yellow filtered light, and the other with just the high contrast blue light/magenta filtered light.
The results help give you a visual appreciation of the respective contributions of the two exposures.
Some of us are more likely to find that the graphs aid us in coming to an intuitive understanding of how things work, while others will get more help from the visual demonstration.

 

[MattKing]

Well I have met digital photographers who are more concerned in getting the histogram curves as they want them, without looking at the image.

And I've a good friend who loves using his step tablets and a densitometer to aid in his darkroom printing. It is great that there is variety in the world.

 

[jonmon6691]

OK. Lead me through how you would use this information to make a split-grade print.

I can merely show you the door Pieter, you must walk through it.

But in all seriousness, I had a question, made a hypothesis, tested it, learned something. And as a bonus I wrote everything down and shared it with the community. That's enough for me. If it doesn't jive with you, that's cool too, I didn't set out to make other people better printers, just to answer a question I had.

 

[albada]

OK. Lead me through how you would use this information to make a split-grade print.

A couple of simple examples of non-split-grade printing:

1. I assume the vertical axes of the graphs are in zones instead of densities. With that, you can look at a test print, and the graph of that grade will tell you how much you need to dodge/burn an area, without making another test strip.

2. Suppose you have the shadows correct in your test print, and now you need to change grade to fix highlights. The two curves will tell you how much to change exposure in order to preserve shadows. (This technique works for preserving any tone, not just shadows).

These two advantages alone would cause some folks to print those graphs and hang them on the wall by the enlarger.

 

[Sirius Glass]

As posted several pages ago:
I start the split grade with the strongest magenta file with time exposure strips across the paper. Once best print is found, I make a print that way and then use strongest yellow file with time exposure strips across the paper. From that print I now have the exposure for the magenta and yellow filter and make the print. At that point I can start burning and dodging with the magenta filter. Then I can work out the burning and dodging with the yellow filter.

This discussion inspired me to do a bit of a study on split grades using a step wedge and some excel kung-fu

I started by bracketing "all" the mixtures of Grade 0 and Grade 5 since I wanted to see if there was a difference between split grade vs an intermediate grade.

Here's starting with Grade 5, then progressively adding more Grade 0 on top for each print (Blue is the start)
View attachment 315327
Here's the opposite, starting with Grade 0 then adding more and more Grade 5 on top this time
View attachment 315328

Then I printed each grade on its own and tried to pick one of the lines from above to see if there was a match

Grade 1
View attachment 315329
Grade 2
View attachment 315330
Grade 3
View attachment 315331
Grade 4
View attachment 315332

This may be obvious to other folks but I was short of surprised to see that there was no difference between split grade or intermediate filters, at least for the base exposure (dodging/burning is a different story).


Note that I'm using a Beseler 23Ciii with a variable contrast head, not sure if this would be somehow different with individual filters.

While all your work shows what happens to a theoretical print, I rather see a real print made by following my method from post 99. The results are easy to see and if one wants to see the magenta only print and the yellow only print one can quickly reproduce them. No charts and no tables to look at.

 

[jonmon6691]

While all your work shows what happens to a theoretical print, I rather see a real print made by following my method from post 99. The results are easy to see and if one wants to see the magenta only print and the yellow only print one can quickly reproduce them. No charts and no tables to look at.

I think people are misinterpreting my post. These graphs are not guides or cheatsheets or reference material. The point is to visualize how blending grades affects the tonal scale. They help show understand how turning the "knobs" (or knob in the case of the 23ciii) of split grade printing affect any given print. I won't be printing these out or referencing them in the dark room, they just help me understand how the paper works better.

 

[Sirius Glass]

I think people are misinterpreting my post. These graphs are not guides or cheatsheets or reference material. The point is to visualize how blending grades affects the tonal scale. They help show understand how turning the "knobs" (or knob in the case of the 23ciii) of split grade printing affect any given print. I won't be printing these out or referencing them in the dark room, they just help me understand how the paper works better.

Self research is a good thing to do. Now I understand. Thank you.

 

[Rmaydana]

A great set of shots Jim. I watched several videos on this by our own Greg Davis who posts here on Photrio and Dave Butcher an Ilford master printer. Both speak of what is happening with the process and things like not confusing contrast with exposure etc but these pics of yours really brings it out in front of your eyes With grade 0 you see the effect of overexposure which can look as if it is better for contrast but isn't and then with grade 5 on top of the grade 0 it is almost as if the face is coming out of a kind of a mist to demonstrate that at some point the face has both the highlight detail in the tee shirt and the necessary contrast and shadow detail.

pentaxuser

Hi, I'm interested in watching the videos you mention, do you have the link? thanks