RE: Density Base OHP and Stouffer
My measurement with a densitometer in UV mode gives the following. Stouffer 21-step tablet, Step 1 = 0.10 Stouffer 31-step tablet, Step 1 = 0.10 Pictorico base, 0.18 Crystal Clear (PhotoWarehouse) base, 0.06 Sandy King At 3:48 PM +0200 11/24/06, Loris Medici wrote: I don't have a densitometer too but I clearly remember people reporting base density of Pictorico as something like log 0.15, and most graphics films - like the ones that Stouffer use - base density is something like 0.05. Therefore there should be around 1/3 stop (0.15 - 0.05 = log 0.10) STP difference between the two. I use Photowarehouse Ulfrafine Crystal Clear transparency and I think its base density is something like 0.10 (0.05 less than Pictorico) and this is completely consistent with the facts: a) My printing times w/ Ultrafine are faster than w/ Pictorico b) When I put the transparency material over the Stouffer step tablet (31-steps) so that half of the tablet is covered (that way I can see the density difference between the Stouffer tablet alone and Stouffer tablet + inket substrate - I think this is covered in Mark's book, IIRC that was a trick that Sam Wang suggested) I get exactly 1 step difference between the two. Just use the trick mentioned in (b) and you'll see how many steps difference you get with your material... From that point, its easy to calculate the necessary exposure adjustment. Regards, Loris. -----Original Message----- From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca] Sent: 24 Kasžm 2006 Cuma 05:39 To: alt-photo-process-l@sask.usask.ca Subject: Density Base OHP and Stouffer I don't own an actual densitometer. My scanner coupled with VueScan puts Pictorico OHP at either LogE of 0.08 or 0.10 and it puts my Stouffer tablet's Step 1 (clear base) at between 0.04 and 0.06. Does this sound close? Do most people use 0.04 or 0.05 (or something else) when calculating the printing time between the two? 0.05 is a bit more convenient because it's 1/6 of a stop. The resulting error is rather small but I'm just wondering. Thx.
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