The late Phil Davis used to do a demonstration at his workshops designed to show that choice of developer and developing methodology makes a much bigger difference in the look of the negative and ultimately the print than the brand or type of film used. Sorry I don't remember the details of exactly what he did but I think he did this in most of his workshops (I attended two and he did the same demo in both), maybe someone else does.
I second your suggestion of using The View Camera Store to do testing. I've made the same suggestion here many times. They do it faster, easier, and likely for less money while providing more information than one spends doing their own testing. That said, doing one's own testing is an excellent learning tool.
I'm not aware that "the digital world is supposed to make things easy." In my experience scanning and printing digitally makes things harder (but potentially better).
Brian Ellis
Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
a mile away and you'll have their shoes.
And I thank Ken Lee for filling in that blank left in Sandy's article on the Unblinking Eye.
Particularly: The meaning of contrast index, in terms of normal values, for people who did not read the BTZS book before reading the article on Pyrocat.
Rick "who actually had to look at the Wikipedia article on sensitometry to understand the log-exposure axis--every 0.3 is a stop" Denney
To be clear, a contrast index of 0.5 is normal for printing with Silver Gelatin.
On the BTZS charts, the Contrast Index is listed as G with a bar over it, which means Average Gradient. It's the average slope of the contrast curve. In other words, given a certain amount of exposure, how dense the negative becomes. When contrast is low, even a lot of exposure gives little density, and the curve is rather flat: its slope or gradient is low. When contrast his high, even a little exposure results in a lot of density: the slope of the curve is rather steep, IE the gradient is high.
Actually, Sandy's article has a table - at the top of the same page to which I have referred - which shows the recommended Contrast Index for different media.
That table is another piece of information which is worth its weight in gold, as is the statement "Most processes have means to control contrast but it is good practice to always start with the best negative possible for the process."
Some feedback...
Visit pyrocat-hd.com for the suggested development times.
16 minutes could be too much, depending on agitation. The negative should look "thin".
TMX is a great film.
You should look at the pyro developers/negatives as a "variable contrast developer/negative". Scan them in color and pick the channel closest to the target contrast.
The graphs on page 1 and 3 of the article, are different: they show Exposure on the X-axis (horizontal), and Density on the Y-axis (vertical). It's interesting to see that the stain density follows the visual density, only it's steeper - and given that UV-sensitive processes need steeper (contrastier) negatives than Silver, the prints we make on either media will have similar appearance, with no need for correction. As Dakotah rightly points out, it's all about the prints.
Last edited by Ken Lee; 26-Mar-2012 at 15:58.
Yes, the dual purpose character of pyro stained developers is a real plus for photographers who print with their in-camera negatives in both silver and pt/pd (and other UV sensitive processes). This has been known for a long time. Edward Weston comments on it in one of his day books, as I recall with reference to a negative he made while in Mexico.
Sandy
For discussion and information about carbon transfer please visit the carbon group at groups.io
[url]https://groups.io/g/carbon
I think this is probably related to my issue. I'm too used to looking for 'thick' negatives, which especially given that I am restricted to scanning for the time being, is a habit worth breaking, as is eye-balling it. I haven't any time for more testing since I posted, but I have been reading and glad this sparked an informative (for me) discussion. Particularly thankful to Ken for the very thorough posts, thanks for taking the time. And Sandy thank you for chiming in, hope you don't take any of this as a slight on your work... Hopefully I'll have some new negatives in the next day or four to at least comment on in lieu of doing some more rigorous testing.
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