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#31
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Toe speed of TMAX 400 (was fridge and heat problems)
Michael Scarpitti wrote:
(Phil Glaser) wrote in message . com... Donald Qualls wrote in message news:LjKGc.21080$JR4.19215@attbi_s54... What format are you using? 6x4.5, 6x6, and 6x9 (all 120, obviously). All in antique cameras, in case lens design makes a difference. But I won't see your reply -- I've gotten tired of your ranting and the ranting you inspire. -- I may be a scwewy wabbit, but I'm not going to Alcatwaz! -- E. J. Fudd, 1954 Donald Qualls, aka The Silent Observer Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm Opinions expressed are my own -- take them for what they're worth and don't expect them to be perfect. |
#32
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Toe speed of TMAX 400 (was fridge and heat problems)
Michael Scarpitti wrote:
(Phil Glaser) wrote in message . com... Donald Qualls wrote in message news:LjKGc.21080$JR4.19215@attbi_s54... What format are you using? 6x4.5, 6x6, and 6x9 (all 120, obviously). All in antique cameras, in case lens design makes a difference. But I won't see your reply -- I've gotten tired of your ranting and the ranting you inspire. -- I may be a scwewy wabbit, but I'm not going to Alcatwaz! -- E. J. Fudd, 1954 Donald Qualls, aka The Silent Observer Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm Opinions expressed are my own -- take them for what they're worth and don't expect them to be perfect. |
#33
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Toe speed of TMAX 400 (was fridge and heat problems)
"Severi Salminen" wrote in message ... When film is developed to a lower CI, for instance for use in condenser enalarger, it must be developed less and the speed will be lower than that give by the ISO test. For most film an adjustment to a one paper grade lower contrast will require an increase in exposure of about 3/4 to 1 stop. The difference in printing contrast between a diffusion enlarger and a common partly diffuse condenser enlarger is about one paper grade. This puzzles me. I allways thought that condenser enlargers only increase the contrast of the final print - nothing more, nothing less. If we first decrease contrast (developing less, agitating less etc.)and then increase the contrast back to normal using a condenser enlarger, why would one have to expose at different EI? Shound't the decrease in development negate the effect of using condenser and thus not call for any change in EI? Example, using diffusing enlarger, EI = (say) ISO/2 and we develop "normally" and get: Zone I at 0.10 above fb+f (so the used EI is "correct") Zone X at 1.30 above fb+f Let's assume that it prints very well. Let's also assume that condenser enlarger increases contrast by a factor of 1.25. So using condenser, EI = ISO/2 and we develop now a little less: Zone I at 0.08 above fb+f (now the used EI seems to be too high) Zone X at 1.04 above fb+f Now using condenser the above "becomes" 0.10 and 1.30 above fb+f - actually only the resulting densities at the print change but... So why would I increase EI at the latter example? If I increase the EI to get Zone I at 0.1, the result is that Zone I prints as 0.125 (1.25 x (0.08+0.02)) and Zone X as 1.325 (1.25 x (1.04+0.02)). That would be incorrect, right? Regards, Severi Salminen I see what you mean here. When the degree of development is changed the density of all parts of the image are changed. The denser parts change faster than the less dense parts, so the contrast changes. The exposure required to produce a density of log 0.1 above fog and base for a negative having the contrast required for printing on "normal" paper on a diffusion printer will not be sufficient to produce that density when the development is reduced to produce a negative for a condenser printer. So, in order to maintain the minimum density the exposure must be increased or there will be a loss of shadow detail. Another way of looking at this is to consider the minimum contrast necessary in the toe region to print shadows with any detail. Since the overall contrast is lowered by reducing development the gradient or contrast of the toe will also be decreased. Because the toe has lower contrast than the main body of the curve the exposure may fall on a part where the gradient is so low that even the increase in contrast from the light source will not bring it up enough to print. The ISO speed measuring method specifies a contrast about right for contact printing or diffusion enlarging. When the development is reduced to lower the contrast the ISO speed is no longer valid. Since there is virtually no safety factor in the ISO measurement there is not much room for error on the underexposure side. This can get critical when the development process loses some speed. OTOH there is lots of latitude on the overexposure side, as much as 12 stops for some films, so a little increase in exposure is always safer than a little decrease. In any case the exposure change between a diffusion negative and a condenser negative is about 3/4 stop. Note that because color film is not affected by the scattering of light which results in the "Callier effect" or change apparent density depending on the specularity of the light source, its contrast remains about constant with diffuse or condenser light sources so it needs no change. -- --- Richard Knoppow Los Angeles, CA, USA |
#34
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Toe speed of TMAX 400 (was fridge and heat problems)
The exposure required to produce a density of log 0.1
above fog and base for a negative having the contrast required for printing on "normal" paper on a diffusion printer will not be sufficient to produce that density when the development is reduced to produce a negative for a condenser printer. So, in order to maintain the minimum density the exposure must be increased or there will be a loss of shadow detail. Is the above totally correct? I have to explain my example in the previous post a bit more. All the numbers below refer to densities above fb+f. Let's say that 1.3 prints as Zone X on diffusion enlarger ("DIF" from now on). Let's also say that 1.04 prints as Zone X on condenser ("CON"). Let's also assume that 0.6 prints as Zone V on DIF. Shouldn't we be able to conclude that 0.48 prints as Zone V on CON (1.04/1.3 = 0.48/0.6)? If that is the case then we should be able to also conclude that if 0.1 prints as Zone I on DIF, then 0.08 prints as Zone I on CON (1.04/1.3 = 0.48/0.6 = 0.08/0.1). A: If the above is NOT true, then you seem to be saying that the difference between CON and DIF is not only contrast but also that it alters the curve shape. Is Callier Effect about changing contrast (mathematically speaking applying only a k-factor to the H&D curve) or does it indeed alter the curve shape non-linearly? B: If the above IS true, then one should not need to change EI at all when switching from DIF to CON as Zone I was printable with no additional exposure. Only the development time should be changed to reduce the film contrast to be able to print Zone I and Zone X. I have no means to test this in real life so that is why I ask. Regards, Severi Salminen |
#35
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Toe speed of TMAX 400 (was fridge and heat problems)
The exposure required to produce a density of log 0.1
above fog and base for a negative having the contrast required for printing on "normal" paper on a diffusion printer will not be sufficient to produce that density when the development is reduced to produce a negative for a condenser printer. So, in order to maintain the minimum density the exposure must be increased or there will be a loss of shadow detail. Is the above totally correct? I have to explain my example in the previous post a bit more. All the numbers below refer to densities above fb+f. Let's say that 1.3 prints as Zone X on diffusion enlarger ("DIF" from now on). Let's also say that 1.04 prints as Zone X on condenser ("CON"). Let's also assume that 0.6 prints as Zone V on DIF. Shouldn't we be able to conclude that 0.48 prints as Zone V on CON (1.04/1.3 = 0.48/0.6)? If that is the case then we should be able to also conclude that if 0.1 prints as Zone I on DIF, then 0.08 prints as Zone I on CON (1.04/1.3 = 0.48/0.6 = 0.08/0.1). A: If the above is NOT true, then you seem to be saying that the difference between CON and DIF is not only contrast but also that it alters the curve shape. Is Callier Effect about changing contrast (mathematically speaking applying only a k-factor to the H&D curve) or does it indeed alter the curve shape non-linearly? B: If the above IS true, then one should not need to change EI at all when switching from DIF to CON as Zone I was printable with no additional exposure. Only the development time should be changed to reduce the film contrast to be able to print Zone I and Zone X. I have no means to test this in real life so that is why I ask. Regards, Severi Salminen |
#36
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Toe speed of TMAX 400 (was fridge and heat problems)
Michael Scarpitti wrote:
: Peter De Smidt pdesmidt*no*spam*@tds.*net* wrote in message ... : : I regularly use TMY developed in Xtol in 35mm, 120mm, 4x5 and 8x10 in : outdoor work. It works very well. Given how Mikey exposes and develops : film, I'm not surprised that it doesn't work for him. In particular, TMY : is more sensitive to underexposure and/or overdevelopment than most : other non-Tmax films. An exception would be Fuji Acros. : : -Peter : : Michael Scarpitti wrote: : : Bull****. It's NOT suitable for outdoor work. It sucks because of the : CURVE SHAPE. S-shaped curves are better for outdoor work. TMY has a : U-shaped curve. moron. : : Then I guess the print in front of me, which was taken with TMY : outdoors, must be magic. : : In any case thank you for continually acting like an ass. That way : newbies won't have illusions regarding your knowledge or character for : very long. : : Peter : : P.S. Btw., my densitometer tells me that TMY has a very straight-line : "curve" in Xtol. But that contradicts Mikey, and so I better get it checked. : 'Straight' isn't 'S'-shaped, now is it? Straight isn't U shaped either. You made the claim that TMY had a U-shaped curve. -- Keep working millions on welfare depend on you ------------------- |
#37
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Toe speed of TMAX 400 (was fridge and heat problems)
Michael Scarpitti wrote:
: Peter De Smidt pdesmidt*no*spam*@tds.*net* wrote in message ... : : I regularly use TMY developed in Xtol in 35mm, 120mm, 4x5 and 8x10 in : outdoor work. It works very well. Given how Mikey exposes and develops : film, I'm not surprised that it doesn't work for him. In particular, TMY : is more sensitive to underexposure and/or overdevelopment than most : other non-Tmax films. An exception would be Fuji Acros. : : -Peter : : Michael Scarpitti wrote: : : Bull****. It's NOT suitable for outdoor work. It sucks because of the : CURVE SHAPE. S-shaped curves are better for outdoor work. TMY has a : U-shaped curve. moron. : : Then I guess the print in front of me, which was taken with TMY : outdoors, must be magic. : : In any case thank you for continually acting like an ass. That way : newbies won't have illusions regarding your knowledge or character for : very long. : : Peter : : P.S. Btw., my densitometer tells me that TMY has a very straight-line : "curve" in Xtol. But that contradicts Mikey, and so I better get it checked. : 'Straight' isn't 'S'-shaped, now is it? Straight isn't U shaped either. You made the claim that TMY had a U-shaped curve. -- Keep working millions on welfare depend on you ------------------- |
#38
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Toe speed of TMAX 400 (was fridge and heat problems)
Michael Scarpitti wrote:
: Frank Pittel wrote in message ... : Michael Scarpitti wrote: : : Peter De Smidt pdesmidt*no*spam*@tds.*net* wrote in message ... : : : : I regularly use TMY developed in Xtol in 35mm, 120mm, 4x5 and 8x10 in : : outdoor work. It works very well. Given how Mikey exposes and develops : : film, I'm not surprised that it doesn't work for him. In particular, TMY : : is more sensitive to underexposure and/or overdevelopment than most : : other non-Tmax films. An exception would be Fuji Acros. : : : : -Peter : : : : Michael Scarpitti wrote: : : : Bull****. It's NOT suitable for outdoor work. It sucks because of the : : CURVE SHAPE. S-shaped curves are better for outdoor work. TMY has a : : U-shaped curve. moron. : : : : Then I guess the print in front of me, which was taken with TMY : : outdoors, must be magic. : : : : In any case thank you for continually acting like an ass. That way : : newbies won't have illusions regarding your knowledge or character for : : very long. : : : : Peter : : : : P.S. Btw., my densitometer tells me that TMY has a very straight-line : : "curve" in Xtol. But that contradicts Mikey, and so I better get it checked. : : : : : 'Straight' isn't 'S'-shaped, now is it? : : Straight isn't U shaped either. You made the claim that TMY had a U-shaped curve. : Depending on the developer and dilution, it can be straight or : U-shaped. But in any case, the curve is markedly different from Tri-X, : etc. THAT is the point. That's correct the curve of TMY is superior to that of tri-x. -- Keep working millions on welfare depend on you ------------------- |
#39
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Toe speed of TMAX 400 (was fridge and heat problems)
Michael Scarpitti wrote:
: Frank Pittel wrote in message ... : Michael Scarpitti wrote: : : Frank Pittel wrote in message ... : : Michael Scarpitti wrote: : : : Peter De Smidt pdesmidt*no*spam*@tds.*net* wrote in message ... : : : : : : I regularly use TMY developed in Xtol in 35mm, 120mm, 4x5 and 8x10 in : : : outdoor work. It works very well. Given how Mikey exposes and develops : : : film, I'm not surprised that it doesn't work for him. In particular, TMY : : : is more sensitive to underexposure and/or overdevelopment than most : : : other non-Tmax films. An exception would be Fuji Acros. : : : : : : -Peter : : : : : : Michael Scarpitti wrote: : : : : Bull****. It's NOT suitable for outdoor work. It sucks because of the : : : CURVE SHAPE. S-shaped curves are better for outdoor work. TMY has a : : : U-shaped curve. moron. : : : : : : Then I guess the print in front of me, which was taken with TMY : : : outdoors, must be magic. : : : : : : In any case thank you for continually acting like an ass. That way : : : newbies won't have illusions regarding your knowledge or character for : : : very long. : : : : : : Peter : : : : : : P.S. Btw., my densitometer tells me that TMY has a very straight-line : : : "curve" in Xtol. But that contradicts Mikey, and so I better get it checked. : : : : : : : : : 'Straight' isn't 'S'-shaped, now is it? : : : : Straight isn't U shaped either. You made the claim that TMY had a U-shaped curve. : : : : : Depending on the developer and dilution, it can be straight or : : U-shaped. But in any case, the curve is markedly different from Tri-X, : : etc. THAT is the point. : : That's correct the curve of TMY is superior to that of tri-x. : Not superior, different, and not as well suited for outdoor work. Why? : Outdoor daytime work typically contains a bright sky. The bright sky : produces flare in the lens which ends affecting the shadow areas most, : where it reduces contrast. TMY has LOW shadow contrast, which does not : benefit from this flare. The shadows look very mushy therefore. On the : other hand, the bright sky itself gets very dense because of the high : contrast of TMY in the upper densities. The result is a negative with : weak, flat shadows and unprintably dense skies/highlights. Tri-X and : other films with S-shaped curves counter-act the problems of outdoor : photography by having higher contrast in the shadows and softer : contrast in the highlights, which is precisely what is needed, and : precisely the opposite of TMY, the worst film of all time. Maybe if you learned to properly expose and develop film you wouldn't be having the problems with the Tmax films. -- Keep working millions on welfare depend on you ------------------- |
#40
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Toe speed of TMAX 400 (was fridge and heat problems)
Michael Scarpitti wrote:
: Frank Pittel wrote in message ... : : Maybe if you learned to properly expose and develop film you wouldn't be having the : problems with the Tmax films. : I do know how to expose and develop film properly. Part of that : knowledge consists of knowing that some films are best suited for : studio work while others are better suited for outdoor work. Some of : us have actually read Kodak's technical publications and have : undertood them. Others, such as you, just spout **** from your ass. The dreck you used to have on your website says that you don't know how to expose or develop film properly. Some of us have actually taken the time to properly expose and develop film. We have also used the Tmax films outdoors and don't have the problems that you claim occur. As always the proof is in the doing and you don't know how. -- Keep working millions on welfare depend on you ------------------- |
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