From: Larry Roohr (larry.roohr@comcast.net)
Date: 08/29/03-08:19:58 AM Z
Hi Mark,
It wasnt too late, but I did hit the sheets. I hope reality isnt too far off of how I imagine this so this isnt just a big rathole.
If the model I'm using (that I made up in my head) is correct then a 51% gray for this hypothetical area of film would get 51 black dots. With quadtones (or color) it would use some mix of them all to arrive at 51% depending on how the driver algorithm works. It would have black, 75%, 50%, and 25% ink to mix up to get any tone in the agregate. I know the actual ink densitys are very different than this but same idea. It would use more dots of lighter ink than the black ink only gray did. Paul Roarke's method for his VM inks on the MIS website colorizes in an interesting way to get a good mix and ramp with the grays in the color positions, the Sundance driver does the same essentailly with the colorizing step built into the driver.
Have you successfully profiled Pictorico OHP? I've tried a couple methods with no luck at all. On my 1280 with OHP theres a real nasty color shift about 3/4 of the way up the ramp that I havnt been able to do anything about.
You know, I spend way too much time worrying about this stuff and too little time photographing and printing. When I have time to spend again I may just get a 2200, use Dan's curve, and be done with it.
Larry
----- Original Message -----
From: Ender100@aol.com
To: alt-photo-process-l@sask.usask.ca
Sent: Friday, August 29, 2003 12:32 AM
Subject: Re: Archival qualities of Pictorico OHP film.
Larry,
I'm not trying to be a pain in the ass, just trying to understand this....
Earlier you said that to get a printed 50% tone you would:
print using half the dots with 100% black ink (I'm assuming like the Epson black ink)
while on the other hand you would
print 100% of the number of dots with 50% gray ink using quadtones to get a printed 50% tone.
Following this, I was asking what would you use with quadtones to print a 51% tone, if you used 100% of the dots of a 50% gray to print a 50% tone... how many dots of 50% gray do you use to print a 51% tone? I think we ran out of dots when we used 100% of them.
Or is it way too late for us to be discussing this?
By the way, I looked up the quadtones again produced by Lyson and MIS and the sites I found still show they are to be used with the older Epson printers, not something like the Epson 2200. I'm wondering if newer printers with their variable dots and ultra teeny weeny picoliter dots might make this somewhat a moot point... or, maybe you could just buy the black ink from their different cold, neutral or warm tone set and use one of those as your black cartridge and print with "black" ink only.
On the other hand, since I am about to go into serious sleep deprivation soon anyway and will be totally unaware of what I am saying I will quickly add that—a decent printer profile will pretty well give you a smooth ramp and a fairly neutral gray scale using color inks. I just made a profile using MacBeth's system for my Epson 2200 and am about to do the same for my Epson 10000. With a well profiled printer using color inks to make a negative, maybe the very slight magenta or green cast you might still get would have little if any effect on the negative used for alt photo. Even if it did, your curve SHOULD adjust for it anyway. Or if it is slightly green, just call it a pyro neg. And instead of 4 inks to dither with quad blacks, with the 2200 and ultrachromes, you get seven. That's a lot of dithering. ;)
Maybe there is someone out there successfully using quadtones to make negatives and has done some comparisons and can shed some light on their superiority if any. That would be interesting to hear about.
Mark Nelson
In a message dated 8/29/03 12:44:01 AM, larry.roohr@comcast.net writes:
51
----- Original Message -----
From: Ender100@aol.com
To: alt-photo-process-l@sask.usask.ca
Sent: Thursday, August 28, 2003 11:28 PM
Subject: Re: Archival qualities of Pictorico OHP film.
Then how many dots would you use to print a 51% tone?
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