Unsharp Masking Technique

Chuck_P · Jan 27, 2009

Tonight, at our photography club meeting, we had a guest speaker, a professional photographer who has studied with Howard Bond and John Sexton; I would like to keep the name silent for now.

The skinny of the post is he showed us some photographs (most were 11x14), most of which he said he employed the unsharp masking technique. Although I believe the photographs were very good, fine compositions and printing, I must say that I was not impressed with the sharpness he claims they possesed-----I simply did not see it. They appeared no sharper than some of my 11x14 prints in TMX developed in D-76 1:1. He said there was no way to get prints as sharp unless the technique was employed. I asked him what film he used and developer---TMY (old) and Xtol.

I left there tonight soundly questioning what I saw, but only to myself as I did not verbalize my feelings. I mean, he was obviously a professional and who am I, just a hobbyist. Still, I was not impressed with his claims. I just thought I would share that, any thoughts?

MurrayMinchin · Jan 27, 2009

Booooo to this unknown photographer for not showing you the original, unmasked prints for comparison purposes!

But the question got under your skin, didn't it? When this happens to me, it usually means there's an intriguing kernel of truth which may be worthy of testing with my equipment and materials to find if it'll work for me.

I've never tried an unsharp mask, but when I first tried a contrast reduction mask (raises only the shadow values of a print) and then a shadow contrast increase mask (puts back way more contrast within the shadows, and gives good solid blacks) on a print, I noticed a marked increased in sharpness in the masked print right away, compared to the original print.

Murray

Chuck_P · Jan 27, 2009

MurrayMinchin said:
Booooo to this unknown photographer for not showing you the original, unmasked prints for comparison purposes!

Well, I would be lieing if I said it would not have helped to have seen them, but my point was that the prints he showed, looked no sharper than others I have seen of that size with TMX 100 without the masking process. I made the point of asking him if he thought the same sharpness could be achieved with TMX and Rodinal---he said "no, you can't do it". Like I said, I liked his photographs, I just question that claim.

keithwms · Jan 27, 2009

CPorter, if unsharp masking doesn't impress you, then consider yourself lucky!

Lopaka · Jan 27, 2009

MurrayMinchin said:
Booooo to this unknown photographer for not showing you the original, unmasked prints for comparison purposes!

Murray

I agree. The point in demonstrating the value of a certain technique is an honest comparison.

Bob

bighilt · Jan 27, 2009

Reminds me of the story of the Emporer's clothes.

phfitz · Jan 27, 2009

Unsharp masking was started at Kodak in the 1930's to help with map making, it would allow printing ultra-fine detail without burning out the major details. This was the time and place of high performance condenser enlargers, using a diffused enlarger may just absorb most of the benefits.

David A. Goldfarb · Jan 27, 2009

Unsharp masking increases edge contrast, so it probably depends on how you look at the print. If you saw a side-by-side comparison of an unmasked print and a masked print at normal viewing distance, for instance, the masked print should look sharper, if it's done right. But if you examined both prints under a loupe, you might decide that they're about the same, or in some parts of the print the unmasked print may look sharper.

bobwysiwyg · Jan 27, 2009

OK, here goes my dumb question for the week. What is an "unsharp mask" in the analogue world? It's a new term to me. How does it work, how does one use it?

keithwms · Jan 27, 2009

Well, by duping, you prepare a mask for the unsharp component of a neg, and you print with that mask aligned to your neg, thus producing sharper edges in the print. Diffuse edges look sharper. Although most necomers will associate the technique with the photoshop filter of the same name, unsharp masking can be done in an entirely analogue (albeit laborious) way.

Its just a way of emphasizing high frequency detail with respect to low frequency "unsharpness."

David A. Goldfarb · Jan 27, 2009

The mask is made with one or more layers of transparent material like mylar or acetate between the original and the film to be exposed for the mask. By varying the exposure for the mask and the distance between the original and the film, the effect can be controlled. Because of the interleaving material, the mask will be unsharp, hence the name. The unsharp mask is printed in register with the original, and if it works, it improves edge sharpness and local contrast.

Kirk Keyes · Jan 27, 2009

phfitz said:
using a diffused enlarger may just absorb most of the benefits.

It works well with diffusion enlargers as well. It's being able to go from a softer printing paper to a higher contrast printing paper that gives the increase in contrast. The type of enlarger doesn't really play into it. You can even do it for contact prints if you like.

bobwysiwyg · Jan 27, 2009

David,

Thanks for the detailed explanation.

Chuck_P · Jan 27, 2009

keithwms said:
CPorter, if unsharp masking doesn't impress you, then consider yourself lucky!

Keith,
Not sure what you mean by this but it sounds like a good thing.

keithwms · Jan 27, 2009

CPorter said:
Keith,
Not sure what you mean by this but it sounds like a good thing.

I should have been more clear What I mean is, if you can get the kind of results you want without unsharp masking, then good for you. I don't mean that in an insulting way... (just in case that's how it came across!)

Matthew Gorringe · Jan 27, 2009

CPorter said:
Tonight, at our photography club meeting, we had a guest speaker, a professional photographer who has studied with Howard Bond and John Sexton; I would like to keep the name silent for now.

The skinny of the post is he showed us some photographs (most were 11x14), most of which he said he employed the unsharp masking technique. Although I believe the photographs were very good, fine compositions and printing, I must say that I was not impressed with the sharpness he claims they possesed-----I simply did not see it. They appeared no sharper than some of my 11x14 prints in TMX developed in D-76 1:1. He said there was no way to get prints as sharp unless the technique was employed. I asked him what film he used and developer---TMY (old) and Xtol.

I left there tonight soundly questioning what I saw, but only to myself as I did not verbalize my feelings. I mean, he was obviously a professional and who am I, just a hobbyist. Still, I was not impressed with his claims. I just thought I would share that, any thoughts?

What format did your tutor use to produce the 11x14" prints? It seems possible that the larger the negative, the better the potential for an increase in apparent sharpness, but the less the need... You are right to question what you saw.

After a year of experimenting with unsharp masking, making my own registration frame, trying different amounts of diffusion and most of the other variables, I've come to the conclusion that the real benefit of the technique for me is in allowing me to use a higher grade of paper to get more local contrast in certain areas and still control overall contrast. This can work well if you use it sparingly and with judgement as Kirk and David have already mentioned.

I use 6x9cm film and I think that, if you want to increase apparent sharpness, the technique is more suitable to larger formats. This is due to the absolute nature of the unsharpness of the mask. The way the sandwich is put together when copying gives some control over how unsharp your mask is but I haven't yet been able to reduce the level of unsharpness in the copy positive so that actually produces an increase in sharpness in the print for 6x9cm negs printed to 12x16".

I'm using Duratrans above the sandwich and only one film base thickness between the emulsions. I do occasionally see edge effects if I compare prints side by side but the apparent sharpness doesn't seem greatly increased. I don't see the pictures becoming less sharp either and the increase in contrast does make things look crisp. I'm now trying to find ways to reduce the degree of diffusion to better accentuate the edges in the final print.

In the end the only way to see what's going on is to have a go yourself. Making a registration frame is cheap and easy (and probably essential for medium format and smaller). The technique is very useful but not just for increasing sharpness, and frankly, do you really need to increase sharpness anyway?

Loren Sattler · Jan 27, 2009

I have scanned a couple of Howard Bond's articles relating to the unsharp masking technique. You will not be able to discern any difference in print sharpness, but there is an explanation of how to make a mask and the benefits in your print.

Howard Bond is master printer, long time teacher of photo workshops and columnist for Photo Techniques magazine. He has been a fine art photographer since the 1960's or 1970's living in Ann Arbor, MI. Many museums collect his prints. For many years he offered black and white workshops in his home teaching the zone system, beginner and advanced printing, large format photography and later the unsharp masking technique. The workshops were hands on and very educational. As part of his teaching methods, students would study beautifully printed photos, either his own or examples from Ansel Adams or other master photographers. Over the years, I had the pleasure of attending two of his workshops.

For the sharpest printing for large format or medium format film, he promotes unsharp masking. He showed us examples of older 11 x 14 enlargements from 4 x 5 conventional negatives and then more current prints using the unsharp masking technique from the same negatives. There was a noticeable improvement in apparent sharpness and local contrast with the unsharp mask prints. As a consequence I believe that over the years, he migrated from 11 x 14 and 8 x 10 negatives to 4 x 5 unsharp mask negatives for most of his work. If you ever have the chance to see his work up close, it is truly remarkable stuff. He is a master photographer and printer in the truest sense of the word.

A bonus for his students is an invitation to an annual reunion of former workshop attendees where prints of former students are passed around for viewing. The quality of the work shown at the reunions is a testament to his teaching skills and craftsmanship in the darkroom. He retired from doing workshops about 1 year ago.

Note, my article scans would not upload. If you want an email copy, send me an email and I will attach them to a response. Send to: lcs7@bex.net

analogsnob · Jan 27, 2009

The mask here is another piece of film exposed by contact with the negative with something like Herculene drafting film between them to produce an out of focus positive. This positive is sandwiched with the negative to change its printing charactoristics usually lowering contrast.

The sharpness increase comes, as stated above, from the accentuation of edge contrast from the halo of the unsharp mask. It is difficult to see unless there is lots of fine detail and can cause problems with large even tone areas, skys, sandy beaches and the like.

The effect of the mask can be thought of as extremely accurate dodging. Depending on how it is made a mask can lower contrast, increase contrast, and reinforce blacks among other things.

With the controls available in b&w -film and processing paper contrast etc -I do not mask b&w very much but it was a daily thing in printing Ilfochrome. Look up "Masking Ilfochrome" here on APUG to get the specifics of making masks. The basic procedures are the same but color control obviously does not apply.

phritz phantom · Jan 29, 2009

unsharp masking is really going beyond my means of contrast control.
a picture which i normally expose 18sek at f11 and grad 3 needed a three minute exposure (f4) at 170M and extensive bleaching afterwards. and still no acceptable blacks (in my eye).
i will try a lesser density mask (not that it was overly dense anyway). my wild guess is: lesser density range in the mask, gives more contrast in the print? and what about contrast in the mask? how does higher/less contrast in the mask affect the print?

edit:
what about developing the mask in a staining developer?

analogsnob · Jan 29, 2009

The amount of change a mask produces is a function of its strength which is basically controlled by developing time. Exposure controls how far up the scale the correction goes and it does add to total print time.

The challenge in making a mask is to give little enough developing time. Use something like HC-110 dilution b diluted further 1:1 and develope about 2 minuits in a tray at 68degrees.

The above treatment with FP4 will give something in the range of 15% or .15 gamma. That is about as heavey as I would go to start. With Ilfochrome we masked somewhere between 10 and 30% but the density ranges were much greater so we had more "headroom" with B&W the density range is somewhere under 1.80 so the mask has to be quite lite to not overflatten the image.

I would not use a pyro formula because the stain will add one more "wild" variable to the mix. You might consider the negative version of a highlight mask- here it holds the deep blacks out of the mask to keep the zip but cut the contrast up the scale a bit. The highligh (deep shadow mask) is made on line film(Kodalith or similar) and D-11 expose so only the deepest blacks have density (If 1 mask does not give you enough density stack 2 or more together) use the highlight in register with the original while making the mask. The deep blacks will be clear on the mask.

Unfortunately this is trial and error keep good notes. If too flat develope the mask less, midtones to snappy- add exposure.

analogsnob · Jan 29, 2009

I guess I shouldn't do this this late. The last line should read --If the print is too flat develop the mask less. If the print has too snappy midtones but ok contrast add exposure to the mask. The mask will look pretty useless when made correctly it will be very flat and light. If it looks anything like a good positive its too heavy.

phritz phantom · Jan 29, 2009

ok, i see my mistake now.
i used hc110 and did 10 minutes in dil.E (same as B 1:1).
i'll try a lighter mask tomorrow.

Chuck_P · Jan 31, 2009

Good to see that the thread is still alive------I am among the 1.35 million folks that have been impacted by the ice storm that hit earlier this week throughout nearly all of Kentucky and the Ohio Valley. My mom just got power back and so am able to check my email other web related things. No power at my house, except essentials with a generator. Oh well, such is life.
_________
Keith,

I did not take offense to what you said earlier---just wasn't sure what you meant. But absolutely, I am very pleased with the sharpness I've been getting with TMX, and look forward to a bit more defined edge sharpness when I test TMX with Rodinol.

pentaxuser · Jan 31, 2009

bobwysiwyg said:
OK, here goes my dumb question for the week. What is an "unsharp mask" in the analogue world? It's a new term to me. How does it work, how does one use it?

Have a look at Lynn Radeka's site where there are examples and theory on the subject. He's your side of the water so hopefully a google search will easily reveal him. I have his site somewhere but don't know how to link. Sorry

I was very impressed by what seems to be achievable but of course at a price in terms of equipment and time and effort.

pentaxuser

payral · Jan 31, 2009

here it is:
http://www.radekaphotography.com/maskingkits.htm

Unsharp Masking Technique

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