Ideal Densitygreenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
A recent discussion on pdn left me trying to reduce the density of my typically very dense negatives in effort to achieve better image quality. I expose film as carefully as I can in accordance with Zone principles; but I use PMK pyro as my developer, and I have grown to love the look of a dense pyro neg so much that the neg itself became a finished product for me--at, I believe, the expense of my prints; occasionally, at more expense the greater the density. So I have started to reduce my development times fairly dramatically to see what happens.
So far, I have been relying on low-Zone density to determine my new times, i.e., assuming the shortest time which brings up the lows is sufficient time, indeed is probably the "ideal" time. But I think I have gone a little to far in the other direction, and have noticed a loss of separation in some of my negatives in the mid and high values, which must be countered with quite excessive contrast at the printing stage (I used to print typically at 50-75cc's of magenta, now I am typically at 100cc's or more). The difference, though, is that I have detail in the highs of a greater quality than with my dense negs, just no separation.
I don't use a densitometer. But I am starting to think I should buy one, for the following reason: Question:
Should I be trying to match my original exposures with a densitometer at the development stage? By which I mean measuring the highlights and making sure particular Zones register in the same place, and thus come up with my new times based on that?
I hope I have asked this clearly...
ps I use roll film, 120 typically, and so I don't have the luxury of developing each frame perfectly according to the original luminance (can't afford another Pentax 67 right now either for plus/minus dev't). I think I might be asking to achieve the impossible.
Thanks all. shawn
-- shawn gibson (SeeInsideForever@yahoo.com), January 17, 2000
If you have a spotmeter, then put a lens in front of it and call it a densitometer. If you don't have a spotmeter, then get one.
I don't know if PMK is different (others can advise), but with conventional developers, varying the development time doesn't change the low densities much. Exposure levels control the low densities, and development times control the high densities. Don't base your development times on the low densities.
I don't understand how you can have detail in your highlights, but with 'no separation'.
-- Alan Gibson (Alan.Gibson@technologist.com), January 17, 2000.
Before getting a densitometer (if you really need one at all), get a ten step gray scale and include that in some scenes. Makes it far easier to see what's happening with exposure and development. You can look at the neg to be sure you haven't lost separation, and you can look at the print for same. You may choose to alter the range for effect, but at least you'll know what's there to begin with.
-- Conrad Hoffman (email@example.com), January 17, 2000.
>>I don't understand how you can have detail in your highlights, but with 'no separation'.
I mean there is nothing "blown-out" like in my dense negs, just lacking contrast, i.e., flat. Boy I really should get a grip on some of these terms. Apparently, I don't know what "modeling" is either...
...Also I use a gray card and 10 'stop' grayscale of Johannes Itten's Art of Colour, which is produced to close tolerance. I usually look at the card, look at the subject value, then look at the grayscale, judge the distance in value, and meter accordingly, usually adding 1/2-1 stop for the shadows (though if my model is wearing dark clothing which is important to me, I'll meter the shadow of it and stop down 3-4 stops, and hope for the with development...).
...Also I used to use the spotmeter in my Contax, now from a borrowed camera, soon from a Seikonic L508...to which I will add the attachment.
-- shawn gibson (SeeInsideForever@yahoo.com), January 17, 2000.
The film exposure is what controls the minimum density in your neg, and development time/concentration controls contrast or iow density of the high end.
Your use of pyro is what's compressing the high end.
-- John Hicks (firstname.lastname@example.org), January 17, 2000.
Should you decide to get a densitometer, be aware that the PMK's yellowish stain will throw off your density readings somewhat. My initial readings of PMK negs on my densitometer resulted in strange densities; they did not agree at all with negs processed in other developers (D76, HC110, etc.).
Gordon Hutchings recommends a filter (I'm sorry, I don't have his book in front of me at the moment to tell you which filter!) for reading PMK negs with a densitometer.
Good luck, Sergio.
-- Sergio Ortega (email@example.com), January 17, 2000.
Poor mans densiometer is a greyscale negative (mine is from 0.15 to 1.65 log density) combined with lightmeter (e.g. Gossen Variosix, bought second hand in Dublin). Now adjust the enlarger that at max density (e.g. 1.65) your lightmeter still reads a value (Variosix: -2.5 EV at ISO 100/210). As 17.8*24 cm is my std. size I use this setting at lens full open, reading with empty carrier 2 EV, now meter every zone, down to 1.65 density, which is about -2.2 EV. Plot now density versus EV.
Using a negative meter it at the same condition and you can get the density values from the plot, including the contrast/density range.
All given EV values are only correct for my enlarger and have to be determined for each enlarger individually, call this calibration.
Two weak points:
measurements require lens wide open @2.8 so values in the edges are ~0.3 EV smaller. densities higher than 1.65 can not be measured. Both restrictions are caused by a lack of light output.( Or make the enlargment smaller e.g. 9*13 cm (about quarter size)and add -2EV to the value measured, so a total of -4.5 EV would a density log ~ 2.3-2.5)
BUT, it is cheap 12.5$ (not 12.5K$)for a grayscale, and gives reasonable results.
-- Wolfram Kollig (firstname.lastname@example.org), January 18, 2000.
John: That's gotta be it. I've come to the conclusion that I am giving way too much exposure. I usually meter the face, which I open up 2 stops for given it's approximate distance from 18% (sometimes I use the graycard if it's a face I'm unsure of); but then I compensate about 1 stop just to make sure I'm bringing up the low's enough. Somehow, a few friends of mine think this is excessive, ehich I have always said, NO, Adams would say it's fine, even maybe I should be doing more to concentrate on the shadows during exposure. But I am starting to think they are right? But now some good news, and sort of wierd, too:
As some may know I switched from 35mm to a Pentax 67, non-metering. I just also bought a Metz CT60. I don't have metering capabilities for it yet, so I've been using GN/D to get my aperture. I add about 1/2 stop per wall of bounce, and otherwise I only open up 1/2 stop over the distance for straight-on flash. MY NEGS with the Metz have been WONDERFUL; great density, no blown-out highs, no flatness.
-- shawn gibson (SeeInsideForever@yahoo.com), January 18, 2000.
PS thanks everyone for the metering suggestions. It is simply going to be a matter of getting an L508, can't avoid it; and I just got job, so hopefully I will have a meter soon for flash. shawn
-- shawn gibson (SeeInsideForever@yahoo.com), January 18, 2000.
Every minilab around usually has a densitometer. Usually they have nothing against, if you ask to use it for a couple of minutes to meter a couple of negs..... So you really don't need to buy a densitometer.
-- Sakari Makela (email@example.com), January 18, 2000.