Originally Posted by hortense
I am sorry but I still do not follow your thinking on this...an unsharp mask does not increase the negative density range (contrast) of the camera negative. It decreases it.
Since the unsharp mask is a positive image of the camera negative it offsets the density range of the camera negative. The way that I think about this is...the unsharp mask has density where the camera negative has low density...that in effect decreases the density range of the camera negative when the mask is combined with the camera negative at the printing stage. That is why when we print the negative/mask sandwich that we are increasing the contrast filtration on the enlarger to offset this compression that the USM brings.
So the best negative for unsharp masking would be one that has a higher then normal density range (contrast) and would, when printed alone, be printed at a grade 1-2.
A negative, that by itself, would be printed at grade 3 1/2 or 4 would have a lower then normal density range (contrast). If we were to take this negative and prepare an USM the addition of the mask we effectively lower the density range (contrast) of the negative still further. Once this were done, we would no longer have any more filtration to dial in to offset this lower contrast that the USM/negative sandwich would exhibit.
unsharp mask is not about sharpening
An unsharp mask is intended to improve the local contrast, not to produce a sharper image. The "sharper look" of an unsharp masked image is a "side effect" due to the increase of the acutance, product of better local contrast and a microscopic line created by the shadow that takes place between the layers of the mask.
Originally Posted by Daniel Lawton
Donald, Hortense and you are in agreement.
Originally Posted by Donald Miller
He is just suggesting that if you have a neg that prints without a mask at grade 4, and then you add a mask, which as you correctly say, lowers the practical overall contrast of the neg/mask combo, then you will then be forced to use a paper with a grade higher than 4. He is recommending that one not put themselves into this position.
As you say, you will probably have better results if you develop the original neg to a higher contrast range if you are going to be using a mask.
Thanks everyone for the replies. I did check out the Alistair Inglis site regarding pinregistering systems but they only make them for large format 4x5 and up. I made a second attempt and the results are better but still a ways off so I'll give it another go later on. Dan you make a good point about "apparent" sharpness being a side effect of contrast reduction. It is this sharp "look" I am going for. In order to simplify the process I have been using Ilford ortho for my masks so I can process it under a safelight and I am processing it just like paper using extra-diluted Dektol from last weeks printing session. My spacers have simply been fixed out clear pices of film.
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Now split grade printing is a beneficial means of printing some negatives. It allows very good control of burning some specific regions within a print at higher or lower contrast but it does not affect the overall contrast in the same way that unsharp masking does. I do find that sharp masking does allow even more control in this regard then split grade printing.
I don't claim that there are no differences between the contrast control available through unsharp masking and split grade printing, only that for me, the gains have not been worth the expenditure of time and effort.
It was not the convenience of burning in different parts of a neg with different filters that initially led me to adopt split grade printing, although that certainly is one of the main benefits. It was the actual difference in the appearance of the tones, particularly the midtones in the print. I could see a difference in a midtone in a print made with a single exposure with a combined Magenta/Yellow filter pack and one made with a full exposure through each of the filters in sequence (doesn't matter in which order). To my eyes, the midtones had a "glow" about them that they didn't have in single exposure printing. It might be just my imagination, but I don't think so. A corollary benefit for me has been the sheer ease of getting a good work print on the first try so frequently.
So I might be motivated to adopt unsharp masking for prints where I couldn't get the results I wanted (and suspected I could get) with my split grade method, but for the most part, I've been content with my results. I do occasionally make use of local or global bleaching to raise a particular highlight value.
While this is taking this thread away from the original question. I will respond to your post that was directed to me.
I will reiterate, that I would hope that this is not a potential conflict arising from the belief that one printing method is inherently better then another printing method. As I said in my earlier response to you, I think that all of these are tools that would beneficially be adobted to specific instances. It is up to the individual photographer to learn the tools and when to apply them.
I was thinking about this yesterday. I don't recall anything ever having been written that outlines the benefits of each of the printing procedures. Both their beneficial effect and their offsetting detrimental effect. Under what ciricumstances to use them based upon the characteristics of the negative and the characteristics of the printing paper. Perhaps you have. If you have please let me know because I have thought of writing a procedure for that purpose.
My thoughts on writing something would follow along the following questions....what are the benefits of unsharp masking? When would it be used? What are the beneficial effects? What are the detrimental effects?When would it be recommended? Under what circumstances would it would not be recommended? What are the differing effects of contrast reduction masking as opposed to print pre flashing?...for another example. Additionally, determining the same set of criteria for each of the other printing procedures/manipulations including split grade printing, contrast enhancing masking, contrast reduction masking, pre and post flashing of the paper, sharp masking etc...
This material, if I were to write it, would be supported by densitometric documentation of the actual effects of each of the processes.
Let me know, if you will, your thoughts on this. Would it be something that would help?
Why not just search for 'unsharp mask darkroom'?
Donald, I think this would be a landmark piece of photographic writing if you were to do that. I can't think of a book or article where all these things have been compared, especially if you do it in depth. I say go for it!
Originally Posted by Donald Miller