U of S | Mailing List Archive | alt-photo-process-l | Re: Density Base OHP and Stouffer

Re: Density Base OHP and Stouffer

I measured visual density of some substrates this afternoon. Unfortunately my X-Rite can't measure UV densities, so these readings are not that usefull, but they give an idea about how clear these substrates are. But beware: even a very clear substrate might be a perfect uv blocker! Sandy King reported on this list that there was a 0.14 difference between visual (0.04) and uv (0.18) density for the pictorico base.

These are my readings:

Pictorico: 0.043
Agfa CopyJet: 0.042
Ultrafine Crystal Clear Inkjet Film: 0.031
Perfect Proof High density Inkjet film: 0.030

Perfect Proof (http://perfectproof.com) combines a clearer base with a very smooth and high density coating and is my prefered substrate for now. Available in Europe and US at about the same price as CopyJet and Pictorico (US).


On 24-nov-2006, at 14:48, 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.


-----Original Message-----
From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
Sent: 24 Kasõm 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.