Colour Neg/Zone System?greenspun.com : LUSENET : Large format photography : One Thread
Does anybody have any advice regarding contrast control with colour neg?
Is it possible to alter tonal range with changes in exposure/development - and how does this affect colour balance?
Any thoughts? Many thanks......
-- Stephen Vaughan (firstname.lastname@example.org), March 04, 2002
With C-41 materials and process the subtle contrast controls are minimal and there are color shifts which are more evident if you shorten the processing time.
The best approach is to really get to know your film and make the best possible negative and then (and you may not like this answer) do your manipulation work in Adobe photoshop or a similar program.
-- Ellis Vener Photography (email@example.com), March 04, 2002.
A related question: Is the EI for color film determined the same way as with black and white? Is Zone I .01 over film base + fog? Could the density be read with a black and white densitometer? If a color densitometer is needed, what channel would be used?
-- William Marderness (firstname.lastname@example.org), March 04, 2002.
For B&W you "expose for the shadows and develop for the highlights". For Color "Expose for the highlights, and fill the shadows".
This have worked pretty fine for me, at least when flash use is suitable. I use this even when developing in a prolab.
-- Enrique Vila (email@example.com), March 04, 2002.
Enrique is completely wrong. For colour negative you also must expose for the shadows and let the highlights fall where they may. This will give you a good rich negative with lots of choice for printing emphasis and full detail in shadows for scanning if you so choose. And colour negative contrast can be manipulated somewhat in development, perhaps by as nuch as the equivalent of a full grade in black and white, but (and this is an important but) colour printing materials have a very limited range compared to black and white printing materials so that contrast manipulation by development of the negative has a limited usefulness. Extending development slightly, perhaps ten to fifteen percent, if you do your own colour neg processing will raise the highlight density relative to the shadow density significantly and give a snappier print but in making such a print you are bound to lose some shadow detail, which because it is present in the negative can be restored to some degree by careful dodging. Of course, the best contrast control for contrast reduction is using a form of unsharp masking, but that is a lot of work. So to sum up: Expose for the shadows, expose genrously. You will get lots of shadow detail and nice tight minimal grain. For very low contrast subjects, moderate extended development can provide a useful contrast increase with minimal colour shift. Experiment and have fun!
-- David Kaufman (firstname.lastname@example.org), March 04, 2002.
Thanks David - that confirms the way I have been working so far. There seems to be a good deal of latitude with the highlights so long as you expose for shadow detail. I think Enrique was answering for Transparency film not neg..... Thanks........
-- Stephen Vaughan (email@example.com), March 04, 2002.
For color transparency film, you definitely want to expose for the highlights and let the shawdows fall where they may, although one has some control after the negative's been exposed. You lose the highlights in transparency film, and you're dead.
I realize that Stephen was referring to color negatives, but perhaps this that to which Enrique was referring.
-- neil poulsen (firstname.lastname@example.org), March 04, 2002.
For sure, give color negative film plenty of exposure. For low contrast scenes give a bit more. Ellis is right about using digital tools to extract all the information you pack into the film. Its pretty amazing what you can do by these techniques and not need much if any filtration or messing with processing times. NPS rated at 100-125 is gonna give you loads of scene information, holding shadows and highlights as well.
-- Henry Ambrose (email@example.com), March 04, 2002.
there is a way to increase contrast, but I know of no way to decrease ist. Increased Contrast C-41-Development requires a seperate bleach process as it was defined in the original C-41-Process. It will not work with a bleachfixer. The steps are as follows: 1. develop (normal time/temperature) 2. fix (normal time/temp) 3. bleach (normal time/temp i.e. 6:30) 4. intermediate exposure (white light) 5. develop (normal time/temp) 6. bleach (normal time/temp) 7. fix (normal time/temp) 8. rinse
You may repeat the steps 2-5 to further increase contrast. You may gain up to one f-stop (resembles a Push Process). Bleach and Developer do exhaust faster, because of repeated activity. On the other hand, the fixer will be effective as normal, because the total amount of silverhalogenides do not change.
-- Thilo Schmid (firstname.lastname@example.org), March 05, 2002.
I feel that if you manipulate c41 to much you will get cross overs that are nearly impossible to correct for. Process normally (exposing for the shadows) and print on a higher saturated paper. Kodak has NC and also VC and of course there is always Fuji papers that are a bit more saturated... You really don't have that much control as yopu do with B/ W! Cheers
-- Scott Walton (email@example.com), March 06, 2002.
I work exclusively with color negatives in combination with the Zone system. I have found that color negs can record a greater light range than b&w negs and can be subject up to n-4 contracted development to control contrast. I could not increase contrast by increasing development. Increased development just makes the overall negative from shadows to highlights thicker. Thus, I have never been able to n+1, n+2... development.
Crossover is not a problem. When it does occur, it can be corrected for by changing the color pack of the enlarger provided you can even see it on the print. Often, I can detect crossover with the densitometer, but it does not show up in the print.
My claims are restricted to Kodak PRO 100 which is no longer available. At n-3 and n-4, any reds in the shadow will turn to a murky purple or brown. In most cases, when doing landscapes, the shadows contain primarily green vegetation so there is no problem. There are no restrictions for n-1 and n-2; reds appear to hold up well in the shadows.
I can record between 10-11 stops with PRO 100.
To calibrate your film, use the ISO setting that produces a 0.1 density unit in the red above film fog at a Zone I placement.
Hope this helps.
-- Stephen Willard (firstname.lastname@example.org), March 10, 2002.
Stephen, how do you develope your color negs to achieve n-3, n-4 ?
Some words about crossowers. Theoretically, a crossower cannot be corrected by filtering. The color in the shadows are opposite to those in the highlights. But it's possible to filter away one of the colors, this compromiss in case the color failures are not very strong.
-- Jan (email@example.com), March 11, 2002.