New versus old Pictorico

Tomf2468 · Mar 20, 2008

The last of my supply of older Pictorico Premium OHP (with the waterfall image on the box) is gone. I realize I will have to do some testing, just curious what others have found switching to the newer / more opaque stuff from Mitsubishi (with the abstract circle/gems on the packaging)?

Thanks,
Tom

pschwart · Mar 28, 2008

The old Pictorico had a base density of .09; the new Pictorico has a base density of .13. I added 50% (1/2 stop) to my base exposure for the old OHP and am getting equivalent prints. A step wedge shows that the correction curve has not changed at all.

Tomf2468 · Mar 29, 2008

How odd, I haven't had time to do real tests. I still have 1.5 boxes of the old left and don't want to waste it, but didn't want to make my new printer curves on the old stuff.

My first impressions where that the new Pictorico handles curves and color choice identical to the old (matches your findings) and that the new Pictorico was just slightly faster (1/3 stop or less). That is the exact opposite of your findings. I've only been Gum printing these last few weeks. Gum is a variable medium!

It may also be that the base density of the new (and/or old) Pictorico varies with your light source. I would certainly expect the new Pictorico to have more base density in visible light (it is slightly milky rather than clear). It "may" have a lower UV density..... Or gum is just variable enough that I've been tricked!

When I get back to printing Platinum or Kalli, if I still have the old stuff left, I will recheck!

The good news for us Pictorico folks is that the New product seems as good as the old

Tom

sanking · Mar 29, 2008

pschwart said:
The old Pictorico had a base density of .09; the new Pictorico has a base density of .13. I added 50% (1/2 stop) to my base exposure for the old OHP and am getting equivalent prints. A step wedge shows that the correction curve has not changed at all.

Not by my UV measurement. All of the old Pictorico I have measured had a base density of log 0.13.

Sandy King

pschwart · Mar 29, 2008

I used an X-Rite 810 so I wasn't actually measuring UV transmission. What value do you get for the new Pictorico? And how old was the old OHP you measured? Is it possible that the new Ultra Premium OHP was shipping before the packaging was changed?

sanking · Mar 30, 2008

pschwart said:
I used an X-Rite 810 so I wasn't actually measuring UV transmission. What value do you get for the new Pictorico? And how old was the old OHP you measured? Is it possible that the new Ultra Premium OHP was shipping before the packaging was changed?

I don't have any of the new Pictorico and have not measured it. I have used the old stuff for years and have measured it many times with a UV densitometer (Greteg D200-11). The readings in UV mode have always been in the range of log 0.13 or slightly higher.

X-Rite 810 can not measure UV density.

Sandy King

clay · Mar 30, 2008

That is about what I get.

Want to know a weird phenomena with this stuff?

Check the UV transmission density with the emulsion side up and then check it again with the emulsion side down. Bet you get two different numbers.

The first time I did this, I thought I had made a mistake, but after checking it again several times and recalibrating my densitometer, and then having another printer who also has a UV densitometer check it in his shop, I decided that this a real thing.

The moral is if you are using a UV densitometer to help you fine-tune your work, be consistent in your measurements, and if you want to be precise, always measure the stuff with the emulsion side up in your densitometer, since that is the direction that light is moving through pictorico, and should mimic the behavior when you use it as a negative when printing. This assumes, of course, that your densitometer has a light source in the base of the unit. All the ones I have seen are built this way.

The only explanation I can make up on the fly for this behavior is that the light is dispersed by the coating. If your densitometer light source hits the coating side first, then the coating must cause some scattering of the light and a consequent reduction in its intensity. Sounds good anyway.

sanking said:
I don't have any of the new Pictorico and have not measured it. I have used the old stuff for years and have measured it many times with a UV densitometer (Greteg D200-11). The readings in UV mode have always been in the range of log 0.13 or slightly higher.

X-Rite 810 can not measure UV density.

Sandy King

sanking · Mar 30, 2008

clay said:
That is about what I get.

Want to know a weird phenomena with this stuff?

Check the UV transmission density with the emulsion side up and then check it again with the emulsion side down. Bet you get two different numbers.

The first time I did this, I thought I had made a mistake, but after checking it again several times and recalibrating my densitometer, and then having another printer who also has a UV densitometer check it in his shop, I decided that this a real thing.

The moral is if you are using a UV densitometer to help you fine-tune your work, be consistent in your measurements, and if you want to be precise, always measure the stuff with the emulsion side up in your densitometer, since that is the direction that light is moving through pictorico, and should mimic the behavior when you use it as a negative when printing. This assumes, of course, that your densitometer has a light source in the base of the unit. All the ones I have seen are built this way.

The only explanation I can make up on the fly for this behavior is that the light is dispersed by the coating. If your densitometer light source hits the coating side first, then the coating must cause some scattering of the light and a consequent reduction in its intensity. Sounds good anyway.

I just checked a few pieces of Pictorico and there was some variation in the pieces, ranging from log 0.13 up to log 0.20. However, I did not observe any variation in reading based on reading the emulsion or base side.

The UV densitometer is far from an ideal tool for predicting true blocking density for printing with UV processes. The main problem is that UV densitometers read in a fairly narrow bandwidth. With my Gretage D-200II the bandwidth ranges from about 15-30 nanometers around the center wavelength of 373 nanometers. Most UV processes are sensitive to radiation 100 or more nanometers on each side of the point of maximum sensitivity.

The specific result of this is that some readings do not translate to real UV blocking densities. With the HP 9180 printer, for example, a measurement of a PDN color of 255 green has a UV reading of over log 5.0, but the effective printing density is only around 2.4.

Sandy King

clay · Mar 30, 2008

Hmmm. Maybe it is just related to the way the light source on my Xrite UV densitometer works. Interesting anyway.

I agree with you about not taking the UV values from these densitometers as some sort of ground truth. I did an experiment about a year ago, where I printed a Stouffer step tablet on the same sheet of paper as a digital negative (pictorico) step tablet. Now be warned here that underlying premise of this experiment is that the Stouffers tablet is neutral in color.

I then measured the densitometer-measured input transmission density for each tablet and graphed them both against the output print density. I found the same thing that you did, that densitometer-indicated UV transmission densities that in theory should produce the same output print density in both step tablets in fact did not do so.

This is a fairly painless exercise, and does not even require a calibrated curve, since all you are doing is creating two different H&D curves on the same graph.

sanking said:
I just checked a few pieces of Pictorico and there was some variation in the pieces, ranging from log 0.13 up to log 0.20. However, I did not observe any variation in reading based on reading the emulsion or base side.

The UV densitometer is far from an ideal tool for predicting true blocking density for printing with UV processes. The main problem is that UV densitometers read in a fairly narrow bandwidth. With my Gretage D-200II the bandwidth ranges from about 15-30 nanometers around the center wavelength of 373 nanometers. Most UV processes are sensitive to radiation 100 or more nanometers on each side of the point of maximum sensitivity.

The specific result of this is that some readings do not translate to real UV blocking densities. With the HP 9180 printer, for example, a measurement of a PDN color of 255 green has a UV reading of over log 5.0, but the effective printing density is only around 2.4.

Sandy King

New versus old Pictorico

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