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#11
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"Print So Fine" paper developer
"UC" wrote in message oups.com... All films have slopes that vary over the scale of the negative. 'Separation' is just another term for 'steep gradation'. The slope at any point of a fil'm's curve is an indication of the contrast in that part of the scale. If the slope in the mid-tones is low (e.g., TMY) mid-tone separation will suffer. The slope of TMY is higher in the upper end of the density scale than in the mid-tones. Theerfore, highlight separation with TMY is greater than mid-tone separation. With Tri-X, it is just the reverse. TMY: http://www.kodak.com/global/en/profe...002_0507ac.gif Tri-X: http://www.kodak.com/global/en/profe...009_0490ac.gif In general I have to agree with this. The relation between the tones of the original scene and the tone reproduction on the print are controlled by the response of both emulsions. The response is what is shown in the characteristic curve, sometimes called the H&D curve. These curves vary from paper to paper and from film to film. Note that overall contrast is shown by the slope of the curve. High contrast materials range from their minimum to maximum densities with small changes in exposing light, low contrast materials require a large change of exposure for the same density variation. However, the _relative_ values depend on the distribution of sensitivity of the halide particles, which is what the _shape_ of the curve reveals. A demonstration can be found by comparing two Kodak films: 400T-Max and ISO 320 Tri-X. T-Max is a relatively "straight line" film with a short toe (definition of toe is below). The ISO-320 version of Tri-X has a very long toe, in fact the curve is upward deflected all along its usable length. The difference in tone rendition will evident by thinking about the effect of this in relation to the original scene brightnesses. If you match the two curves for equal contrast index and for the same shadow and highlight densities, you will find that the Tri-X has less density for the mid-grays, so it will reproduce them darker than T-Max. This is sometimes desirable. One can find similar differences in paper curves except that a long toe on paper will result in brighter mid tones. In general, developers have little effect on the shape of the curve. However, additives like Potassium bromide does affect them. Bromide tends to suppress the very lowest exposures, so it has the effect of reducing the usable toe area. Another way of stating this is that it increases the relative contrast of the toe of either film or paper. The effect on film is to suppress fog and, if much is used, to lower speed. On paper the effect is also to reduce fog and to brighten the highlights. Specific developing agents do not have much effect but overall contrast of the paper can be varied a little (for some papers). The variation possible is not nearly so great as for film because film for pictorial use (as opposed to graphic arts use) is developed far short of its maximum possible contrast. Prints, OTOH, are usually developed to their maximum contrast, or at least, to reach their maximum densities. Some so called low contrast developers are merely slow and do not reach this density in normal development times (or sometimes ever). Some developers are selective in a way that does affect overall contrast but the range is limited, certainly less than one paper grade. Again, except for adding bromide or Benzotriazole, there is little effect on curve _shape_. BTW, neither variable contrast or graded papers have consistent curve shape throughout their contrast ranges. In most cases one grade different negatives can be printed to have identical tone rendition by changing the paper grade one step. The same with printing the same negative on a condenser and a diffusion enlarger, but larger variations may show some differences in mid-tone reproduction. Contrast and image color. Image color of prints (and negatives too) depends largely on the scattering of light in the emulsion. This is in turn controlled by the particle size of the silver making up the image. Extremely finely devided silver looks bright yellow (its used as the filter layer in Kodachrome). As it become coarser it shift toward blue. Since the grain size of the image is somewhat due to the developer very active developers that tend to produce coarse grains also tend to produce bluer colored images. Less active developers, for instance Kodak Selectol Soft and Ansco 120 (nearly identical) tend to produce finer grains and warmer images. They also tend toward lower contrast and slower development. Tone Seperation. I am never quite sure what is meant by this. presumably the ability to detect small variations in brightness. This is partly affected by the resolution of the image. Blurry images do not have good separation of anything including tone values since they tend to blend into one another. Partly, it is due to so called local contrast. At the highlight and shadow ends of a print the contrast is lower than in the mid gray area regardless of the paper, film, and developers used. This is because the toe of the film is affecting the shadow area contrast and the toe of the paper is affecting the highlight area. Often, when photographers complain of lack of tone separation in highlights (blocked highlights) its because they are trying to print a greater range of brightness than the paper is capable of reproducing. The only solution to this is burning in, either by hand or by means of a contrast mask of some sort. If variable contrast paper is used the blocked areas can be printed in using a lower contrast filter (with masking). The eye wants to see contrast similar to the original scene so simply lowering the contrast of the reproduction won't look right. As far as any developer claiming to modify the paper curve shape (or film for that matter) the proof is in properly done sensitometric testing. If there _is_ an effect it will show up plainly on an H&D curve. There is a lot of room for errors to creep in this sort of testing so one must be wary tests which are not very carefully designed and controlled. -- --- Richard Knoppow Los Angeles, CA, USA |
#12
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"Print So Fine" paper developer
Nicholas Lindan has written to me and will be posting the response I
sent him, but the claim we make is supported by subjective analysis of the print. We strive to post accurate information on our web site and all product descriptions are designed to help people find what they are looking for. Unlike a lot of other companies in the market, Digitaltruth Photo is run by photographers. Personally, I have used a lot of print developers and based on my own experience if I was looking for a warm-tone image with excellent gradation, then Print-So-Fine would be my choice. Its not a fast developer - typically taking a minute more than a standard developer - so its not for everyone, but I would recommend it to anyone who wants better contrast control. The image appears slowly so it is easier to pull the paper out of the developer before the highlights lose their sparkle. I agree with Richard Knoppow's post, and given that sensitometry is complex I prefer to judge things with my own eye. A print is usually judged by people who look at it and not by scientific analysis; however, we do have people making sensitometric tests and will publish the data as soon as it can be properly assessed. I can assure you that there is no apparent visible loss of density reported by the various people who have made subjective analyses of the prints, so even if the sensitometry shows a technical reduction in density this does not invalidate the experience of actual users. I'd love to publish jpegs on our web site, but there is no way to show the subtlety of the effect on a monitor. --Jon Mided Digitaltruth Photo http://www.digitaltruth.com |
#13
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"Print So Fine" paper developer
A paper developer formulated without hydroquinine (which is what I
suspect this product is) could still give a good D-Max, but would perhaps act slower. If KBr is added, that could also change things, including adding some warmth. It cannot, however, give hugher contrast in the mid-tones if measured objectively, but if the D-Max is ever so slighly less, the mid-tones could APPEAR to be more vigorous in comparison. Digitaltruth wrote: Nicholas Lindan has written to me and will be posting the response I sent him, but the claim we make is supported by subjective analysis of the print. We strive to post accurate information on our web site and all product descriptions are designed to help people find what they are looking for. Unlike a lot of other companies in the market, Digitaltruth Photo is run by photographers. Personally, I have used a lot of print developers and based on my own experience if I was looking for a warm-tone image with excellent gradation, then Print-So-Fine would be my choice. Its not a fast developer - typically taking a minute more than a standard developer - so its not for everyone, but I would recommend it to anyone who wants better contrast control. The image appears slowly so it is easier to pull the paper out of the developer before the highlights lose their sparkle. I agree with Richard Knoppow's post, and given that sensitometry is complex I prefer to judge things with my own eye. A print is usually judged by people who look at it and not by scientific analysis; however, we do have people making sensitometric tests and will publish the data as soon as it can be properly assessed. I can assure you that there is no apparent visible loss of density reported by the various people who have made subjective analyses of the prints, so even if the sensitometry shows a technical reduction in density this does not invalidate the experience of actual users. I'd love to publish jpegs on our web site, but there is no way to show the subtlety of the effect on a monitor. --Jon Mided Digitaltruth Photo http://www.digitaltruth.com |
#14
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"Print So Fine" paper developer
On 10 Feb 2006 07:03:18 -0800, "Digitaltruth"
wrote: there is no way to show the subtlety of the effect on a monitor. --Jon Mided February 10, 2006, from Lloyd Erlick, .... this must be why we talk about it so much! ... regards, --le |
#15
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"Print So Fine" paper developer
I received this from Jon Mided at digitaltruth.com:
... my own test results show a pronounced improvement in tonal separation which appears equivalent to between half and one full grade reduction in contrast; however, the highlights and shadows appear as if no loss of contrast has occurred. To settle the original question: "What does 'Improved Midtone Separation mean'?" -- it seems it does indeed mean _lower_ contrast. Even though I agree with J-D that greater tone separation should mean greater contrast. I'm a photographer first and foremost, and not a scientist, but I ran multiple side-by-side print tests and the results are clear. There are some of us who will only believe a sensitometeric test stand and densitometer results and those who rely on subjective impressions. Myself, if I can't measure it then it isn't there -- an engineering attitude, but do you want to drive over a bridge that is only supported by belief? From Jon's description it would appear a claim is made for an H&D curve that tends to be 'chair shaped': a lowering of mid-tone contrast while high and low tones are left at normal contrast. It would seem that two contact prints through a step tablet and a few minutes at the densitometer would show what is happening. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. To reply, remove spaces: n o lindan at ix . netcom . com Fstop timer - http://www.nolindan.com/da/fstop/index.htm |
#16
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"Print So Fine" paper developer
"Lloyd Erlick" Lloyd at @the-wire. dot com wrote
On 10 Feb 2006 07:03:18 -0800, "Digitaltruth" wrote: there is no way to show the subtlety of the effect on a monitor. ... this must be why we talk about it so much! ... "Oh! let us never, never doubt what nobody is sure about!" Hilaire Belloc "Only issues that can't be settled are worth talking about." Me -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. To reply, remove spaces: n o lindan at ix . netcom . com Fstop timer - http://www.nolindan.com/da/fstop/index.htm |
#17
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"Print So Fine" paper developer
Nicholas O. Lindan wrote: I received this from Jon Mided at digitaltruth.com: ... my own test results show a pronounced improvement in tonal separation which appears equivalent to between half and one full grade reduction in contrast; however, the highlights and shadows appear as if no loss of contrast has occurred. To settle the original question: "What does 'Improved Midtone Separation mean'?" -- it seems it does indeed mean _lower_ contrast. Even though I agree with J-D that greater tone separation should mean greater contrast. Of course. The word 'greater separation' means 'farther apart'. Two points on a steep slope are farther apart than the same points on a shallow slope. The only way this stuff could offer 'Improved Midtone Separation' would be if it modifies the H&D curve by some chemical means, such as adding bromide and omitting hydroquinone. I'm a photographer first and foremost, and not a scientist, but I ran multiple side-by-side print tests and the results are clear. There are some of us who will only believe a sensitometeric test stand and densitometer results and those who rely on subjective impressions. Myself, if I can't measure it then it isn't there -- an engineering attitude, but do you want to drive over a bridge that is only supported by belief? Nope. From Jon's description it would appear a claim is made for an H&D curve that tends to be 'chair shaped': a lowering of mid-tone contrast while high and low tones are left at normal contrast. That would not give Improved Midtone Separation at all, but Worsened Midtone Separation. It would seem that two contact prints through a step tablet and a few minutes at the densitometer would show what is happening. Yup. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. To reply, remove spaces: n o lindan at ix . netcom . com Fstop timer - http://www.nolindan.com/da/fstop/index.htm |
#18
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"Print So Fine" paper developer
I think most of the analysis here is correct. Sensitometry will show
some loss of density, but not to a point where it appears less than a full black on visual inspection. The developer is based on traditional ingredients and cannot perform miracles, but everyone who has used it is impressed by the final image quality and remarks on what appears as improved tonal separation. |
#19
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"Print So Fine" paper developer
"Digitaltruth" wrote
I think most of the analysis here is correct. Well that's the nicest thing anyone has said about us in a long time... Sensitometry will show some loss of density, but not to a point where it appears less than a full black on visual inspection. If there is detail in the shadows you have to stay well away from DMax. A DMax of 2.6+ isn't hard to get, but anything from 1.9 to 2.6 is invisible in the print unless you view it by transmitted light or with an arc lamp. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. To reply, remove spaces: n o lindan at ix . netcom . com Fstop timer - http://www.nolindan.com/da/fstop/index.htm |
#20
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"Print So Fine" paper developer
On Sat, 11 Feb 2006 00:26:27 GMT, "Nicholas
O. Lindan" wrote: unless you view it by transmitted light or with an arc lamp. February 11, 2006, from Lloyd Erlick, Or direct sunlight. Just look at a print in direct sun if you want to see it without sympathy. regards, --le ________________________________ Lloyd Erlick Portraits, Toronto. voice: 416-686-0326 email: net: www.heylloyd.com ________________________________ -- |
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