Weird issues printing negs w/QTR?

Hi all,

This is my first post here and I'm hoping somebody can shed some light on a problem which is driving me nuts!!

I've been making digital negs for palladium prints for 3 years now using QTR. All has been great. A month ago I made prints in my standard way with no issues. Last week I began printing for an upcoming show and the prints are all muddy. I have painstakingly isolated all the variables and it looks like its something to do with my digital negs. I've done a fog test and the paper rinses perfectly clear. When I print through a piece of pictorico, the highlight areas and the "blank" border around my step tablet come out very grey. In fact, when I take the paper out of the potassium oxalate developer I can see a grey sheen where it should be yellow/orange. I've checked all my chemistry and it seems to be fine.

Here's the weird part. I decided to completely redo my QTR curve and the only way I can get the grey highlights to disappear (mostly) is to increase the K, C, M, Y and Boost_K values to the point where the step tablet is clear though to the 22% patch and the rest is very light. Its impossible to linearize at this point (I've tried).

I've been told it may be a "chemical fog"?? (from the folks and Bostick and Sullivan). I tried adding a dilute amount of hydrogen peroxide which has not helped.

The bizarre part is nothing has changed since I last printed.

If anybody has any ideas here, I'd love to hear them!

Many thanks,
Dave

DaveA said:

Hi all,

I've been told it may be a "chemical fog"?? (from the folks and Bostick and Sullivan). I tried adding a dilute amount of hydrogen peroxide which has not helped.


Dave

Click to expand...

Did you mix up some fresh ferric oxalate?

Don Bryant

Here's an addendum:

I just made two prints - one from an old digital neg I made about 6 months ago, the other a true contact print from a 4x5 neg. Both prints came out perfectly.

Yes, I've changed all my chemistry, and given the prints, its got to be something in the creation of my negs. But what???

I'm baffled. Tomorrow I'm going to try making a new step tablet on a friend's 3800 and see what happens.

If I had any hair, I'd pull it out!

dave

Is this a different pictorico? Did you go from ultra premium to just premium? Sorry, just grasping at any idea. The ultra needed much more exposure so that might account for the depressed highlights if you were using the 'plain' premium now.

Or maybe an inkjet nozzle has clogged, might not show up visually but could make all the difference with UV absorption, especially if it was yellow.

If you are using the same profile, it must be something to do with the printer itself, unless you have changed

- computer or OS
- embedded profile in the file (can't imagine this causing so large a problem)

You didn't mention which printer, but if 3800 have you accidentally changed black inks?

Otherwise I guess you might somehow not be getting one ink. Try printing the QTR ink separation sheet on your printer and your friend's printer and compare, either with a UV densitometer or by printing them.

Good luck... Ben

DaveA said:

Hi all,

Here's the weird part. I decided to completely redo my QTR curve and the only way I can get the grey highlights to disappear (mostly) is to increase the K, C, M, Y and Boost_K values to the point where the step tablet is clear though to the 22% patch and the rest is very light. Its impossible to linearize at this point (I've tried).

Many thanks,
Dave

Click to expand...

So since you've upped the dark inks so much your getting way too much blocking thru the midtones. If your using a 2 part curve ( dark inks following K and then lighter inks following LK ) then you can increase the density setting on the LK. The then dark inks won't start to kick in as soon.

Don't know if you use a photoshop curve or numerical for your grey curve=
But you'll need to just make a big move in the middle of the grey curve to darker.

Thanks for the input folks. I'm going to try Rob's approach and see how that works out.

I'm using a grey curve so we'll see what happens!