Darkroom equivalent to PS "overlay" blend mode?

[gdavis]

Hope this hasn't been discussed already. I did a search and find stuff about contrast masking but I think this is a little different.

In PS one thing I like to use a lot is layers with the "overlay" blend mode. I particularly like the way it increases contrast. I'm wondering if there is a darkroom technique that is roughly equivalent to PS overlay? Mainly considering color negs at this point.

From what I've gathered, overlay is sort of a combination of screen and multiply (though simply making two layers and setting one to screen and the other to multiply doesn't produce the same results). As near as I can figure, sandwiching film in an enlarger would be roughly equivalent to the multiply blend mode in PS.

I've been playing around in PS by inverting the original image to make a "negative", then copying that to new layers with various adjustments and blend modes then putting an invert layer on top for the final image to simulate printing color negs on an enlarger. I can get some interesting effects, but can't quite replicate what I get using overlay.

Any ideas, insights or suggested reference materials that might help me?

[Brian Ellis]

The overlay blend mode is, as you note, like a combination of multiply (darken) and screen (lighten), i.e. it increases contrast. It also increases saturation. I never thought it was all that special, I thought you could accomplish the same thing, though with more time, effort, and experimentation, by using curves on an adjustment layer with the normal blend mode (normal because that will increase saturation). And I would think you could do much the same thing in a color darkroom by the use of masks. But since my color darkroom work never advanced to the point of using masks, I'm not sure.

There's a lot of information on the internet about blend modes. I thought this was a good explanation of five of the more important ones. http://www.photoshopessentials.com/photo-editing/layer-blend-modes/ And one of the Lynda.com tutorials on the use of blend modes is very good. You can subscribe to Lynda.com for something like $25 a month, which I did for a couple months and I thought it was well worth the money.

[Drew Wiley]

I is getting more difficult to acquire complete sets of masking equipment, although
if you have machine shop skills you could fabricate your own. Simple masking punches and frames for 4x5 work are still available, and sometimes more serious
graphic equipment comes up used. The really big stuff is still manufactured by
pre-press companies like Ternes, Stroesser, etc. Some of us really enjoy masking,
but it is a complex craft in its own right and capable of many things. Most of the
tasks now done in PS were traditionally done by masking. Simple contrast masking
is the easiest to learn. I believe that optical enlargement combined with LF film
and true optical enlargement is still a cut above digital printing in terms of final
output quality. But it is time-consuming, requires meticulous darkroom habits,
and might involve quite a film budget. If you enjoy darkroom work per se it is worth
learning, especially for printing color tranparencies.

[gdavis]

The overlay blend mode is, as you note, like a combination of multiply (darken) and screen (lighten), i.e. it increases contrast. It also increases saturation. I never thought it was all that special, I thought you could accomplish the same thing, though with more time, effort, and experimentation, by using curves on an adjustment layer with the normal blend mode (normal because that will increase saturation). And I would think you could do much the same thing in a color darkroom by the use of masks. But since my color darkroom work never advanced to the point of using masks, I'm not sure.

There's a lot of information on the internet about blend modes. I thought this was a good explanation of five of the more important ones. http://www.photoshopessentials.com/photo-editing/layer-blend-modes/ And one of the Lynda.com tutorials on the use of blend modes is very good. You can subscribe to Lynda.com for something like $25 a month, which I did for a couple months and I thought it was well worth the money.
Thanks for the link, that's a better description of the blend modes than anything I was able to find. I managed to pretty closely replicate overlay with screen and multiply now. Still haven't figured out how to apply it in the darkroom though.

Ya, if you're just copying the image to a new layer and setting the blend mode to overlay for contrast, you can do pretty much the same thing with curves pretty easily. I do use curves if that's all I'm doing, but when you're using overlay with things like high pass, blur, gradient maps etc. I think it's a little different...

[gdavis]

I guess I should mention that I've used PS for several years and feel comfortable enough with it to do what I want to do. I've gotten kind of tired of it (and digital in general) and realize that much of it is based on darkroom techniques so wanted to learn the original darkroom techniques.

I never got too crazy with PS but I do like to make some creative adjustments and "enhancements" beyond just making a clear "correct" image. So many people see something a little out of the ordinary and automatically proclaim "photoshop", I want to show these people that they don't know what they're talking about ;)

I love the look of transparencies, but from what I've read about printing them I'm not so sure about taking that on. And with E6 kits becoming more scarce... But sometimes I wonder if the masking I want to do would be easier with transparencies vs negs.

[Drew Wiley]

The entire method of masking has to be tailored to both the kind of film used and the print media itself. I had to learn masking for chromes, first Ciba and then dye transfer printing (quite different), then for black-and-white film to silver gelatin
(which I've largely abandoned due to improved films, paper, and developers), and
finally color-negative masking (much more subtle, and not generally needed). The
equipment is pretty much the same for all these, but everything else differs. I you
can get the frames and punches, and enjoy hands-on craft as opposed to PS, I'd encourage experimentation with this.

[gdavis]

A couple people have mentioned frames and punches and I kinda get that part, but where can I find information on what sort of masks I need to make to accomplish what I want to accomplish? I see plenty of info about USM and contrast reduction masks but that's about it. I've seen other masks mentioned by this masking kits website but haven't found any other descriptions. Surely this info must be fairly common in the darkroom world and available somewhere without buying one of this guys kits? No books or anything to recommend? Maybe I should just buy a kit?

[Donald Miller]

A couple people have mentioned frames and punches and I kinda get that part, but where can I find information on what sort of masks I need to make to accomplish what I want to accomplish? I see plenty of info about USM and contrast reduction masks but that's about it. I've seen other masks mentioned by this masking kits website but haven't found any other descriptions. Surely this info must be fairly common in the darkroom world and available somewhere without buying one of this guys kits? No books or anything to recommend? Maybe I should just buy a kit?

http://www.radekaphotography.com/maskingkits.htm

http://www.radekaphotography.com/carriers.htm

http://www.maskingkits.com/maskingbasics.htm

http://www.maskingkits.com/faqs.htm

http://www.maskingkits.com/maskingexamples.htm

http://goodlight.us/writing/saturationmasks/satmask-1.html

http://goodlight.us/writing/luminositymasks/luminositymasks-1.html

Hope this helps.
Donald Miller

[Drew Wiley]

The sources Don gives are a good starting point for masking black and white negs,
and Howard Bond gives workshops on simple unsharp masking for b&W. Color is a whole
different thing, and depends on the specific print medium. But there are plenty of things in older darkroom and graphic arts manuals - it's just that all the films have
changed. Pan Masking film is extinct, but even better results can be obtained with
FP4+ or 100TMax, provided one knows the tricks.

[gdavis]

I appreciate Don's effort, but the first 5 links are all related to the same kits I mentioned previously. As far as I can tell they exist solely for the purpose of selling the kits and don't have any real information about how to actually create any masks, you have to buy the kits (or go to their seminar) for that.

The other two links seem to be PS techniques. Don't know if I'm supposed to be able to extrapolate that to the darkroom or if there's something I missed?

OK, so older manuals have plenty of things but the films have all changed. Does that mean that the older manuals are completely irrelevant now? Or are the principles still the same and just need to be tweaked for the new films? What are some examples of these books that I can look for?

So I need to know the "tricks" to use FP4+ and 100TMax, is this info readily available anywhere? You're starting to sound a little like a magician who doesn't want to reveal his secrets ;) Am I going to have to befriend a darkroom master and convince him to let me apprentice in order to get any guidance in this? :p

I've seen people get vague answers like these in forums when the person asking is clearly in over their head and just asking all the wrong questions but have never been on this end of it before. Am I completely going about this the wrong way? Feel free to tell me if I am. I want to learn this stuff and not looking for easy answers but figured there would be at least some references out there describing techniques so I'm not completely reinventing the wheel through trial and error. But if that's what I've got to do...

[Drew Wiley]

Masks were traditionally used for many different purposes - special effects, contrast
control, hue correction, sharpness control, the list goes on and on, just like the PS
terminology which mimics this. The last guy to publish detailed manuals on technique
was Bob Pace, and this material is difficult to acquire now and partially out of date due
to changes in film choice. Basically, once you learn how to handle the equipment itself,
it's a matter of trial and error learning. Feel free to ask all the questions you wish, but
it's an inherently vague subject until you get your feet wet with basic technique. Besides a registraton punch and matching pin frame, you will need some frosted mylar diffusion sheeting and ideally a b&w transmission denistometer, with a Stouffer step wedge for experimenting. If you are contemplating contrast increase masks for colors negs you will probably being doing a double neg technique. Color corrections can be incorporated if needed by using ordinary b&w contrast filters with pan film. Except for an inherent problem with Newton rings, 100TMax is an excellent masking film if developed in very dilute HC-110. Since very small changes in procedure will have a significant impact in the final print, you need excellent process control (time, temp, agitation). Beyond this, you will need to ask more specific questions in order to get more specific answers. And when it comes to masking, there is more than one way to
skin a cat. Those of us still doing this for color printing have developed differing and
highly personal methods of workflow, so you'll inevitably elicit different answers for
similar problems.

[gdavis]

OK, fair enough. I've been doing more reading and thinking and experimenting in PS and I think I'm starting to wrap my head around this a little more. Thanks for the info, searching on Bob Pace's name actually led me to some helpful info.

How's this for a question? From my experimenting, if I want to manipulate a color negative, in order to achieve what I'm looking to achieve I need a B&W copy of the negative. I want to retain the tonality, not have only pure black and pure white, so I think lith is out of the question? All other BW films I'm aware of are negative films and would create a positive from the negative. Is there a suitable BW film available that would preserve gray tones and create a neg directly (i.e. BW transparency film) or would I be better off making a neg from an interpos with something like TMAX?

[Drew Wiley]

In principle what you're trying to do is fairly easy, but it takes a little practice to
optimize results. First you would create an interpositive on black and white film by
contact registration, emulsion to emulsion. This should be developed to contain all the
relevant tonal scale you need, but otherwise be somewhat low contrast. Then you
would contact expose this to another sheet of black-and-white film to produce the
negative itself. In other words, two steps involved. This basically gives you a duplicate
black and white negative of the original color negative. The difference with a contrast
control mask is that this final version needs to be very weak, typically with a maximum
density of .30 or less, yet give fairly straight-line reproduction of the entire tonal scale
of the original color neg. This requires a special developer, although as I already hinted, HC-110 can be used very dilute with TMax100 to achieve this. You will also
need to use a diffusion sheet between the final pieces of film to achieve a slightly
unsharp mask to aid registration and help apparent sharpness. Plus you will need to
adjust your filter pack in the colorhead exposing light, or add necessary filters to
correct for the orange mask in the original color neg in relation to the spectral sensitivity of the pan film. At the same time you can favor or soften certain hues in
the final print by selective filter use, just like exposing pan film in the field. Many many
things you can do to improve the print. But expect a serious learning curve. It takes
time to experiment.

[gdavis]

Thanks for the info, that was more than I expected with some ideas that I hadn't considered. At this point I'm just hope to get in the ballpark of what I'm envisioning but plenty more options to explore and keep me busy. Should be fun, time to start experimenting :D

[gdavis]

So I tried an experiment, making an enlarged interpositive on 4x5 Portra 160nc from an old 35mm negative. It seems that with my lens stopped all the way down (f/16) I still need an exposure time of a fraction of a second which my timer can't really handle. I'm guessing my options are neutral density filter or a new timer that can do fractions of a second for several hundred dollars :eek:

[Drew Wiley]

For masking work, the interpositive would be made on black and white neg film,
not color. But either way, you'll ideally want to work somewhere in the 10 to 30 sec
range of exposure for precise control. Depends on the film of course, and how
tolerant it is of reciprocity effects.

[gdavis]

Ya, I know the mask should be B&W, I just wanted to see what it would look like (looked pretty much completely black at 1 sec :rolleyes:).

I'm thinking of getting a dimmer to turn down the light source and increase the exposure time.