DB masking advice?

[BHuij]

@albada Good summary, thank you. This is indeed new information for me. If I'm understanding correctly, by flashing through a 00 filter, I was getting the paper closer to its green light threshold but not blue. In my case, it seems that's actually what I would want to do - the blue-sensitive emulsion is the high contrast one that is giving me darker tree trunks than I want, so pre-flashing that emulsion would only result in even darker shadows in the final print.

In any case, I'm not succeeding in getting what I want with preflashing alone. I'll post back when I've had a chance to test out some unsharp masking.

 

[Pieter12]

I have a 6x6 negative from my second ever roll of infrared film (Ilford SFX through a Hoya R72) that I really, really like. As I'm not anywhere near all the way dialed in on exposure and development for this film stock, this negative is very dense and very contrasty.

Yesterday I made a straight print as a starting point. As expected, by the time I got my white-ish foliage to the right tone, my tree trunks were significantly darker than I want them for a final print, even at grade 00.

I lack the number of limbs necessary to simultaneously dodge all of the areas I'd like to lighten during exposure, so for the first time I think I'm going to need to do some masking. All the reading I've done so far says: get a thin frosted acrylic sheet above the negative and tape your mask over the top of that. I can do that. I just don't know what to use for my mask. I have some transparency film I use for alt process digital negs, so I could make a 6x6 inkjet mask. Or I could try a more traditional mask that I make by hand (maybe on the same material?)

How exactly do you go about actually creating dodge masks for enlargement? What materials do you use? How do you control density (is it just guess and check)?

Have you tried split-grade printing this negative? I would print for the tree-trunks and burn the leaves with a 5 filter. Maybe preflash if there isn't enough highlight detail. For me, It is easier to burn isolated highlight areas than to simultaneously dodge the shadows.

 

[MattKing]

the blue-sensitive emulsion is the high contrast one

Actually, all three emulsions offer the same contrast. Where they differ is in their sensitivity. Contrast in the print is controlled by adjusting how the results from each emulsion add up.

 

[DREW WILEY]

No "one-shoe-fits-all" explanation can be adopted. Different varieties of VC paper have somewhat different personalities with respect to achieving DMax. Some do it best using hard blue light only, others need at least some green exposure too to get there. All this impossible to separate from personal esthetic objectives anyway.

But in terms of selective burning in, blue or magenta obviously facilitates the darker values, while green or yellow fills in the highlight texture.

Besides people using the term "contrast" in more than one manner, likewise there's often confusion between emulsion sensitivity per se and sheer filter density issues. For example, blue filters are inherently more dense than green of analogous application, so require longer printing times. Add to that the fact that many enlarger illumination sources are at the warmer or yellower end of the scale, and that compounds the difference. Even with my blue-green Aristo V54 cold light, a maximum deep green 61 filter prints five times faster than a deep 47 blue on most VC papers.

 

[RalphLambrecht]

@RalphLambrecht is there any possibility of sharing the pdf more widely? I'm sure many others would be interested, I myself too.

I will try to upload it here if size allows.

 

[pentaxuser]

Here's some clues from the OP himself: The "target" for this image is something along these lines, I'm just hoping to achieve it in the darkroom instead of on a computer. High hopes that preflashing will help me get there in a way that's repeatable and doesn't involve manual dodging and burning heroics.

He then adds:

In any case, I'm not succeeding in getting what I want with preflashing alone. I'll post back when I've had a chance to test out some unsharp masking.

I wonder if we should allow him to try unsharp masking before offering any further advice and risk overloading him with information

I had no idea or maybe I should say the wrong idea about what he wanted until he showed us a version of what he wants but found that so far our advice has not yet got him to his desired result.

OP, one suggestion I would make is that you use the tools of PS to show us exactly what the desired end result should be and then we all know exactly what you desire and that our joint objective is to get you there via purely analogue means

pentaxuser

 

[Mainecoonmaniac]

I have a 6x6 negative from my second ever roll of infrared film (Ilford SFX through a Hoya R72) that I really, really like. As I'm not anywhere near all the way dialed in on exposure and development for this film stock, this negative is very dense and very contrasty.

Yesterday I made a straight print as a starting point. As expected, by the time I got my white-ish foliage to the right tone, my tree trunks were significantly darker than I want them for a final print, even at grade 00.

I lack the number of limbs necessary to simultaneously dodge all of the areas I'd like to lighten during exposure, so for the first time I think I'm going to need to do some masking. All the reading I've done so far says: get a thin frosted acrylic sheet above the negative and tape your mask over the top of that. I can do that. I just don't know what to use for my mask. I have some transparency film I use for alt process digital negs, so I could make a 6x6 inkjet mask. Or I could try a more traditional mask that I make by hand (maybe on the same material?)

How exactly do you go about actually creating dodge masks for enlargement? What materials do you use? How do you control density (is it just guess and check)?

Have you heard of S.L.I.M.T? https://www.photrio.com/forum/threads/slimt-and-why-you-should-be-using-it.64135/

 

[DREW WILEY]

Hasn't the Geneva Convention banned SLIMT due to it being an especially slow form of unnecessary torture? Sometimes it makes a lot more sense to simply set aside hopelessly stubborn dense negatives and evolve your technique instead. I admit I got caught up in the masking question for its own sake. But a lot of this kind of advice is putting the cart before the horse. Things like masking and flashing and split printing might distinctly improve something in a fine-tuning manner, but aren't of much real value if the basics aren't pegged down first.

 

[albada]

@albada Good summary, thank you. This is indeed new information for me. If I'm understanding correctly, by flashing through a 00 filter, I was getting the paper closer to its green light threshold but not blue. In my case, it seems that's actually what I would want to do - the blue-sensitive emulsion is the high contrast one that is giving me darker tree trunks than I want, so pre-flashing that emulsion would only result in even darker shadows in the final print.

In any case, I'm not succeeding in getting what I want with preflashing alone. I'll post back when I've had a chance to test out some unsharp masking.

I suspect that flashing through a 5 filter will allow you to reduce the main exposure, perhaps lightening the areas that are too dark. It's worth a try.
A side-effect of flashing is that shadows have high contrast, which is what you want.

 

[Andrew O'Neill]

I tend to go the unsharp mask route. You don't need a spacer between the unsharp mask and the negative, either. Just place the mask on top of the negative, emulsion side up. Eye ball registration on a light table with +4 specs I picked up at a dollar store. Tape together. Have worked this way for decades.

 

[DREW WILEY]

The problem with emulsion-up route when exposing the mask (not when printing) is that sometimes you no longer have a neutral mask. Here's why : you are passing light through the back of the film with its strong antihalation dye coloration. So if your original has any color bias (like a color film original or even a black and white original with any distinct hue like pyro stain), there will be a differential effect in the mask itself. That's why some people working in that manner choose FP4 as their masking film, due to its neutral gray back.
Registering the sandwich visually atop a light table is fine for initial learning purposes or just incidental masking, but is a guaranteed recipe for insanity on any routine basis. We large format photographers might be classified as nuts anyway, but I don't like actually feeling insane. Probably the smartest investment I ever made in my life darkroom-wise was to get the very best punch and registration gear made at the time, which was from Condit.

 

[albada]

I learned the following from Ilford's documents and Way Beyond Monochrome (Ralph Lambrecht).

1. VC paper consists of three emulsions. To reach the paper's d-max, all three emulsions must be at their d-max's.
2. All three are equally sensitive to blue (identical curves).
3. Two of the three emulsions also have some sensitivity to green (i.e., they are sensitive to both blue and green).
4. Green sensitivity is lower than blue (lower contrast).
5. The three have the same threshold when exposed with blue, but their green thresholds differ and are lower than their blue thresholds.

An easy way to remember the behavior of the emulsions is that threshold and contrast of blue are both higher than green.

Consequently, when exposing with only blue, all three curves add at the same exposure, creating a steep composite curve, creating high contrast.
When exposing with a mixture of green and blue, the three curves are shifted (due to differing thresholds), reducing the composite slope, reducing overall contrast.
The threshold-difference is why green affects highlights more than shadows, and why blue affects shadows more than highlights. That threshold-difference is also why blue requires more exposure to reach threshold, but after reaching threshold, blue is more sensitive (higher contrast) than green.

Because all three are equally sensitive to blue with identical curves, pre-exposing (flashing) with only blue will bring all three to their thresholds.

Mark Overton

I want to correct a mistake I made in item 3 in the above explanation.
All three emulsions have some sensitivity to green, but with Ilford RC and perhaps other papers, at least one emulsion has a long shoulder.
That's why it requires much exposure to reach D-max with filter-00; the composite curve has a long shoulder (= low contrast shadows). That shoulder is so long that I regard filter-00 (pure green) as useless. Shortening that shoulder is why I added a little blue even at the lowest contrast setting in my LED controller.

 

[albada]

The problem with emulsion-up route when exposing the mask (not when printing) is that sometimes you no longer have a neutral mask. Here's why : you are passing light through the back of the film with its strong antihalation dye coloration.

Did you mean emulsion-down? If the mask's emulsion is up during exposure, light will not pass through its back. Or is my understanding backwards?

 

[Andrew O'Neill]

The problem with emulsion-up route when exposing the mask (not when printing) is that sometimes you no longer have a neutral mask. Here's why : you are passing light through the back of the film with its strong antihalation dye coloration. So if your original has any color bias (like a color film original or even a black and white original with any distinct hue like pyro stain), there will be a differential effect in the mask itself. That's why some people working in that manner choose FP4 as their masking film, due to its neutral gray back.
Registering the sandwich visually atop a light table is fine for initial learning purposes or just incidental masking, but is a guaranteed recipe for insanity on any routine basis. We large format photographers might be classified as nuts anyway, but I don't like actually feeling insane. Probably the smartest investment I ever made in my life darkroom-wise was to get the very best punch and registration gear made at the time, which was from Condit.

I've been taping masks on a light table for years. No insanity has crept in so far. I've only ever used one mask anyway. If I were using multiple masks then I would opt for a registration system. For basic masking (unsharp)it's not necessary. Also, colour of masking masking film has no bearing when doing black and white. I've even used x-ray film for masking.

 

[DREW WILEY]

albada - some light will pass through the back. And the emulsion itself, along with the film thickness, provides a small amount of diffusion. I worked that way for years. It was a mistake, but not a bad enough mistake to be debilitating. And yes, one can forego a registration punch and pin system. Heck - people hunted wooly mammoths for tens of thousands of years with only spears; but that had its occupational hazards too.

 

[koraks]

Shortening that shoulder is why I added a little blue even at the lowest contrast setting in my LED controller.

Yeah, dito. I did most of my testing with Adox MCP, which just won't hit dmax with only green. By the time it does, halation in the paper itself has destroyed any detail.