mkochsch
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Oh it would take a stretch of -20 to -30 weather here in Winnipeg to force me back into working wouldn't it? :rolleyes:
Just thinking out loud. Here's the idea:
It's (yet) another method for calibrating the printer to the process/negative using the combined black CcMmYK inks. As such it's probably a good choice for gum bichromate and classical cyanotype where density requirements are usually not as demanding. But, that said, it may work for other processes too depending on the printer and the inks.
The method takes the opposite approach to finding a blocking colour. It says "let's leave the printer alone". Just let the printer print at whatever density it wants to print at when you're using combined inks to make black. (We will assume the printer prints with too much density for your given process).
For example, when your inkjet printer prints a 100 per cent black patch (the white point of your print) it can create an opaqueness of something in the order of 1.8 logD with your UV lights. Your emulsion however only requires 1.05 of the scale to use its properties fully.
If you just print your negative straight out with no adjustments we all sort of know the scenario. After establishing a standard print time you come up short on the highlights. In desperation you try over-exposing to try and salvage some of the highlights because overall the negatives range is to long for the emulsion.
If you printed-to-process a stouffer step-wedge and a digitally generated 101 step-wedge on OHP together you would see the stouffer wedge gets its highlight at step 10 or 11 on a T3110 or/and around step 7 on a T2115. And for the purposes of our demonstration let's say the digital step wedge turns white around step 68 on a 101. Here's where the miracle of the curve dialogue steps back into the scene.
You open curves and "lift" your white point for the print up to 32 (see attached image) and apply a "straight line", What you've effectively done is limit the tones which will print. You've "padded" the highlights on the image (see bracketed area "A") on the histogram "pulling" them left, toward the shadows like an accordion player moving the bellows inward.
View attachment 204
Now this doesn't eliminate the need for a tonal adjustment curve. That still would need to be calculated in the usual way. BUT it starts and ends your adjustment curve in the lower-left and upper-right corners. It's two visits for the curve
I can almost hear the screams of "but you're losing tones!!". Maybe with an 8-bit file yes, but maybe not with a 16-bit file they don't seem to be an issue with this technique. To prove this you can open a 16-bit file and use curves to pad out the image. Then after you've applied this go into the Levels command and "fix" the image by tightening up the white point, keep repeating. You would think that you'd get the pumpkin teeth (or some call it picket fence) in the histogram right away but you don't! I didn't see any after five or six iterations of curving off and highlights and then resetting the white point.
Simpler. A throwback, sort of. Less futzing with the printer settings possibly. The advantage (if indeed it is an advantage) to this method is it eliminates the step of selecting and applying a blocking colour for those users who don't require a lot of UV blocking power in their process. Also, printing with combined CMYK inks might more evenly drain the inks from your printer. I seem to blow through a lot of Magenta carts and Yellow when I'm printing digital negatives, which is fine if an when I need a lot of density. There may also be a resolution advantage because the dot count of combined CMYK may be higher per inch. The disadvantages, less potential blocking. If the blocking colour is too black you may revert to a situation where the highlight are printing defacto "black ink only". Questions?
~m
p.s. ...and honestly Native Printer Density is not a hidden anagram for anything.
Just thinking out loud. Here's the idea:
It's (yet) another method for calibrating the printer to the process/negative using the combined black CcMmYK inks. As such it's probably a good choice for gum bichromate and classical cyanotype where density requirements are usually not as demanding. But, that said, it may work for other processes too depending on the printer and the inks.
The method takes the opposite approach to finding a blocking colour. It says "let's leave the printer alone". Just let the printer print at whatever density it wants to print at when you're using combined inks to make black. (We will assume the printer prints with too much density for your given process).
For example, when your inkjet printer prints a 100 per cent black patch (the white point of your print) it can create an opaqueness of something in the order of 1.8 logD with your UV lights. Your emulsion however only requires 1.05 of the scale to use its properties fully.
If you just print your negative straight out with no adjustments we all sort of know the scenario. After establishing a standard print time you come up short on the highlights. In desperation you try over-exposing to try and salvage some of the highlights because overall the negatives range is to long for the emulsion.
If you printed-to-process a stouffer step-wedge and a digitally generated 101 step-wedge on OHP together you would see the stouffer wedge gets its highlight at step 10 or 11 on a T3110 or/and around step 7 on a T2115. And for the purposes of our demonstration let's say the digital step wedge turns white around step 68 on a 101. Here's where the miracle of the curve dialogue steps back into the scene.
You open curves and "lift" your white point for the print up to 32 (see attached image) and apply a "straight line", What you've effectively done is limit the tones which will print. You've "padded" the highlights on the image (see bracketed area "A") on the histogram "pulling" them left, toward the shadows like an accordion player moving the bellows inward.
View attachment 204
Now this doesn't eliminate the need for a tonal adjustment curve. That still would need to be calculated in the usual way. BUT it starts and ends your adjustment curve in the lower-left and upper-right corners. It's two visits for the curve
I can almost hear the screams of "but you're losing tones!!". Maybe with an 8-bit file yes, but maybe not with a 16-bit file they don't seem to be an issue with this technique. To prove this you can open a 16-bit file and use curves to pad out the image. Then after you've applied this go into the Levels command and "fix" the image by tightening up the white point, keep repeating. You would think that you'd get the pumpkin teeth (or some call it picket fence) in the histogram right away but you don't! I didn't see any after five or six iterations of curving off and highlights and then resetting the white point.
Simpler. A throwback, sort of. Less futzing with the printer settings possibly. The advantage (if indeed it is an advantage) to this method is it eliminates the step of selecting and applying a blocking colour for those users who don't require a lot of UV blocking power in their process. Also, printing with combined CMYK inks might more evenly drain the inks from your printer. I seem to blow through a lot of Magenta carts and Yellow when I'm printing digital negatives, which is fine if an when I need a lot of density. There may also be a resolution advantage because the dot count of combined CMYK may be higher per inch. The disadvantages, less potential blocking. If the blocking colour is too black you may revert to a situation where the highlight are printing defacto "black ink only". Questions?
~m
p.s. ...and honestly Native Printer Density is not a hidden anagram for anything.
