Re: continued solarplate notes
Which of your theories are your referring to? The screen/image ratio
Yes. My theory that the ratio is more important than the exposure--that the
exposure just hardens a thicker plate layer of goo, and up to a very large
point one could use a large latitude of exposure from minimal to maximal (I
did 90 seconds to 11 minutes!), but it is the ratio that creates the correct
tonal range and needs to be chosen carefully and then curved to tweak it. I
hope I am explaining this correctly because I am hittin' the hay. The caveat
is, of course, that the combined exposure is within reason--if I left the
plate an hour in the sun I would think it would be completely hardened and
Did you expose image first or screen? How were you creating the poly
plate sandwich? With a contact frame in both instances?
Image second; haven't done the trial with aquatint second yet. Contact frame
both instances as I don't yet have a vacuum frame.
Also, what's the size of the plates you tested? Also, can you post the
brand/model of the UVBL tubes you're using Chris? Sorry if you've already
the KM73 8.5x11 and solarplate 9x12. Edwards 11x14 light unit. F15T8BL GE
Black Light bulbs.
If you're right, and the tests are scalable, I will formally retract my
blanket statement that UVBL is bad for poly plates on the whole, and will
admit that I was wrrr...wrrr...wrong. Unless someone has developed a
better workflow that changes things for the better somehow, I will
maintain that UVBL is definitely a problem when using Solarplates larger
than 8x10, however.
No no no, please don't retract yet. I don't work with larger plates, one,
and the contact frame is all I got, but for small plates under UVBL and sun
I don't yet detect a difference. That doesn't carry much weight IMHO
because that is visual opinion, not fact. And I really need to compare my
plates with same image done under an inside point source, methinks. My test
today was anecdotal re: that point but re: exposure latitude it was
Next would be to do a number of Stouffers at, for example, 2, 4, 8, 16, 32mn
total exposure time with same ratio aquatint to positive and compare the
tonal range. I think, though, the KM73 limit should be under 11 min
combined. With solarplate I could have exposed even longer than combined
I can't believe you are relishing the thought of big plates......
I'm relishing my bed...
In my world, I'm currently recalibrating my standard adjustment curve to
work with the new 7800 in my basement. Just a giant version of the 2200,
really. Ink carts are like the size of VCR tapes, which is pretty wild.
The only high-tech object I own that is larger now is my car. 8-D Max
density is lesser on the 7800, as has been reported, but the 1440 dpi
output I had been using on the 2200 was actually much, much thinner than
the 7800's output at 2880 or 1440. I created the adjustment curve by
looking at the transmissive values of a step wedge printed out using my
old curve on my old printer/media using my scanner. I then printed out an
unadulterated step wedge on the 7800, read the values of it, and charted
the differences. I then built a new curve from that data (several, in
fact), printed them all on an 8x10 piece of OHP, made the plate, made
several prints. Looked at print #4, and tweaked the best curve... Will
wash, rinse, repeat as needed.
I tested the new Pictorico OHP Ultra's last week and found its added base
density to be over the top (way too cloudy white for me and my workflow
with poly plates), so I exchanged it for a roll of the regular Pictorico
OHP. Pictorico wasn't happy, but they were accommodating. :-) I should
have just asked them to send me samples...
I'm hoping the roll OHP isn't much different than the sheet OHP media.
Does anyone use, or recall anyone else using, different curves for roll
vs. sheet standard Pictorico OHP?
I'm also developing another curve for a roll of this AccuArt2 transparency
media (remember that stuff?). I've had a roll of it in my basement for a
couple years now. Has very little base density compared to Pictorico OHP,
which is way better for me than having too much imposed density in the
media's base. Once that's worked out I'm hoping to have some things to
post that aren't just step wedges (though they'll be those too I assure
Now pursuing two leads on the finer 1800 dpi stochastic screens and will
keep you all posted. Also, not sure if I mentioned this, but Harold at
Box Car has confirmed the availability of A1 sized KM73 plates
(23x30-ish). Pricing is comparable to his current prices, however it
takes 2 months to get them from Japan. :-o I'm placing an order soon and
hope my current workflow supports doubling the plate size. If not, I can
always cut them down, as one of my clients who wants me doing bigger
plates for them, reminded me. :-) Wish me luck with that...in about two
Christina Z. Anderson wrote:
Well, results of two tests, for whatever it is worth:
I proved to myself my theory holds water. I did a solarplate at 8 mn
aquatint/8 mn positive in full on direct HOT sun. I normally expose
solarplate 3.5/3.5 to 5/5 under 15 watt UVBL. I got a perfectly beautiful
tonal range of 7 stops from white to black.
Considering that Mike Ware says the sun is several times more powerful
than UVBL (anyone know the exact comparison?) this is enough proof to me
that there is a quite wide range of acceptable exposure and that the
ratio is where it's at.
I exposed a KM73 plate to 8 minutes (!) aquatint but cut the positive
exposure to 3 mn to relate to my 2 mn/45 ratio I found under UVBL with
this plate (haven't tried the 49/41 ratio outside yet) and sure enough I
got a usable image, although a bit on the bland side. Same hot sun,
direct sun, but the deepest black on it corresponds to 1 stop less black
than the solarplate deepest black. This stands to reason since my
solarplate exposure is usually 2.5 to 3.5 more than the KM73 plate
exposure. To have a range of exposure from 49sec/41sec UVBL 15 watt to
8mn/3mn outside full sun is a pretty dramatic indication of latitude.
Interestingly, I don't see a (dramatic or otherwise) difference between
the sun exposed plates and UVBL, yet, anyway. I got four Newton ring
spots still even though I powdered both sides of the screen and positive
and the top side of the plate.
----- Original Message ----- From: "Jon Lybrook" <email@example.com>
Sent: Sunday, April 08, 2007 5:25 PM
Subject: Re: continued solarplate notes
Jon, the Dan Weldon screen isn't that dense at all. I'm getting the
same exposure times as you are, adjusted for my 1000k lamp.
You may be getting the same exposure times at different wattages, and
but we're also using very different screens. 80% density indicates
coverage of dots (dpi), not density of the "tone". Every dot is 100%
opaque - at least that's how the plate should see it with a proper
screen. Both our screens may have "80% density", but the exposure times
(and perhaps ratios) between them will vary using the same light source.
Are you doing the exact same screen/image times as I am? If so, it
could be worth examining, or could be coincidence...I don't know.
That's true, but I'm suggesting it's similar in the end result.
Undercut dots in the screen exposure would lower the density *effect* of
the screen on the plate from 80% to something less than 80%,. In both
cases the dots are smaller, which is what allows more shades of gray to
be produced. There's certain to be other differences...of course. My
point was if that particular author was getting good results using our
plates with 1K exposures for 15 minutes, Chris may well be correct that
the exposure times ratio is more important than the actual times, BUT
I'll bet he gets better results than others using lower exposure times
(assuming the ratio is the important thing) because his dots are
smaller. Just an idea. Difference between 10seconds and 15 minutes for
the same media is quite a variance...
Another thing about longer exposure and the undercutting of dots...
that's not really the same as a finer screen. The dots would be
smaller, but they still number the same per inch so the space between
would just be larger.