Speaking of Underexposure

[DouglasGrigar]

Since I am needling my friend Douglas about his professional 'old school' 24" silver film image setter, I went on record that I miss photographic films for screen making. 

"I'm a silver film lover from the 1970's", but alas most film use stopped at the turn of the century as film companies stopped making it and EPSON introduced the Photo Stylus 3000 for only US$1,100.  Much less than a wet darkroom or image setter.

You know who it was Richard one location had 12 to 16 full time artists the other had over 20 the smaller location alone had three full time “camera people” that did nothing but shoot wet acid processed silver cut sheet film (not PMT even if both locations had PMT in the early days).

When we actually transferred to using an imagesetter we gained a full time artist and could let the camera people do something more productive in the shop.

Anyone remember the horrid metal arc exposure systems, we started there and graded up to three monsters that I have no idea if stuff like that even exists now.

So now I get to bother Richard a bit...

Why don’t any of the emulsion companies ever test product with the low-power units? Does anyone there ever understand the confusion that happens with the sheets included with the product?

Why don’t more makers and suppliers push for the use of exposure calculators (including the excellent one KIWO makes)?

Why do so many suppliers encourage so many to underexpose?

[Frog]

Why did Step Wedge Man and Exposure Lad constantly have to come to the rescue on the old board?

[DouglasGrigar]

My memories of silver film is a bit more tarnished. I got involved with prepress with the introduction of a linotronic 300 running postscript level 1 on a 10 mhz rip. At that time, the linotronic was considered one large step backwards in quality. pre-press was accustomed to 4.0 film density, but the first generation of helium-neon film was lucky to get 3.1 on a good day. Put a newspaper on a light table and put lino film on top of it and the newspaper could clearly be read through the film. It was a LONG uphill battle to prove that lino film was usable.

Inkjet film is an entirely different animal. With silver, all of the silver starts off on the film, then the laser determines where the silver should be removed. With inkjet, the film starts clear and ink is piled on top of it. In the case of inkjet film, there is such a thing as "too much ink".

The Middle Way is the path between the extremes of self-indulgence and self-denial.

I can say outside of the smell of the acid bath processors I don’t remember anything “bad” about silver films, and nothing but good to excellent for silver based film and imagesetters. The one thing I do remember was that the numbers on production output with the imagesetter to justify buying something that cost more than a few years salary of the art staffers was blown out of the water we did not even come close to how much more we were able to produce. The smaller staff alone would average between 3/4 and 1 and a 1/2 rolls of film a day, we had used cameras for so long we were not ready for the ease - of course Adobe separator was released slightly before that and that changed everything.

The film positives we gained from the imagesetters was “da bomb” I have a sample I saved and yes the dots were beautiful lines clear and sharp and the D-min and D-max were a thing of awe... at least compared to the inkjet output that at least is reasonable where folks suffering with the xerox process vellums have the worst of both worlds...

[DouglasGrigar]

Why did Step Wedge Man and Exposure Lad constantly have to come to the rescue on the old board?

Imagine that 

I often think that I end up encouraging overexposure because I see so many problems with underexposure.

I have come across printers in tears of frustration over related issues.

putting under and over exposure on a chart with pro and con (and correct in the middle) it may well be that overexposure could end up with far less “cons” and far more “pros” than underexposure.

I can tell you I have never come across problems with overexposure in the wild because I have only found underexposure and not a single case of overexposure.

[Frog]

getting folks to do a step wedge test, either one step films, or manually moving opaque sheets, opens their eyes at least to what correctly exposed emulsion looks like, compared to over and under exposed.
It's just tough to get some folks to sacrifice an otherwise good, usable screen of each common mesh and emulsion combination. They would rather proceed to ruin three others screwing around insread!

[DouglasGrigar]

getting folks to do a step wedge test, either one step films, or manually moving opaque sheets, opens their eyes at least to what correctly exposed emulsion looks like, compared to over and under exposed.
It's just tough to get some folks to sacrifice an otherwise good, usable screen of each common mesh and emulsion combination. They would rather proceed to ruin three others screwing around insread!

So true, so sad, I do try and fix that...

I don’t talk about less-than-10% dots, because most of the time I am just trying to get new people to stop trying to get 65lpi on a 110 white mesh by underexposing QTX...

How do we get them to print halftones and deal with how they are coating 1/1 sharp and don’t understand why there are problems with the 45 deg. angle dots...

How do we get them to understand the relationship with low-power exposing units and reasonable quality positives with some dealers pushing vellum and parasites pushing pathetic “work-arrounds” and blasting users of inkjet RIPS?

[tpitman]

A lot of people are simply lazy, and want you to just tell them the correct exposure time for their emulsion using their 500w halogen worklight exposure unit that might be 6 inches or 6 feet from the screen, with an old t-shirt, some foam, and a concrete block piled on top for compression. We all started somewhere not very pretty, but too many can't be bothered if results aren't instantaneous and easy like they saw on YouTube.

[Orion]

A step wedge test will determine correct exposure with the film supplied in the test kit. If the films you output aren't the same dmax value (more than likely less opaque) then real exposure times would be less?

[Frog]

A manual step wedge test done with a typical film of yours could be more relevant.

[RichardGreaves]

Speed was an issue, silver imagesetters are (or were) very fast when up against an inkjet.

Amber always sucked, sorry guys, but it always sucked, I have a few samples left over and throw them on the unit every once and a while to show someone how they suck even up against an inkjet (with the special film).

adidas/Reebok in Indy was the last place I saw two big Agfa image setters. Hardly an average art department.

Douglas, would you bring me a small clipping to the Indy Printwear Show, of the AmberLITH you have so I can measure it on my UV densitometer?

[Frog]

Ya know,  I had always thought that the Ruby was a better blocker, and we sacrificed that for the better visibility of cut lines through the Amber.
One thing is sure, the Ulano (and other brand) tubes make great containers for fishing rods.

[RichardGreaves]

getting folks to do a step wedge test, either one step films, or manually moving opaque sheets, opens their eyes at least to what correctly exposed emulsion looks like, compared to over and under exposed.

It's just tough to get some folks to sacrifice an otherwise good, usable screen of each common mesh and emulsion combination. They would rather proceed to ruin three others screwing around insread!

Since my first feature article in Screen Printing in the late 1980's "Measuring Diazo Exposure" I have promoted using a US$10 Stouffer T-2115 transmission on every exposure to monitor stencil hardness.

No screen needs to be sacrificed. Every screen has the test scarred in the stencil. The math is easy to correct your NEXT exposure. Ready, Fire, Aim. Perfect for fluctuations in emulsion and degrading UV sources.

Properly used, a single 5" test positive should last a lifetime. I have them with me always and sell them at shows for US$10 - pretty girls get them for free. You can surprise most Nazdar reps by asking them to lookup "21step".

[yorkie]

A single hit of Epson 1400 yellow ink is UV opaque enough to produce screens. (cyan and magenta are UV transparent)

[Frog]

getting folks to do a step wedge test, either one step films, or manually moving opaque sheets, opens their eyes at least to what correctly exposed emulsion looks like, compared to over and under exposed.

It's just tough to get some folks to sacrifice an otherwise good, usable screen of each common mesh and emulsion combination. They would rather proceed to ruin three others screwing around insread!

Since my first feature article in Screen Printing in the late 1980's "Measuring Diazo Exposure" I have promoted using a US$10 Stouffer T-2115 transmission on every exposure to monitor stencil hardness.

No screen needs to be sacrificed. Every screen has the test scarred in the stencil. The math is easy to correct your NEXT exposure. Ready, Fire, Aim. Perfect for fluctuations in emulsion and degrading UV sources.

Properly used, a single 5" test positive should last a lifetime. I have them with me always and sell them at shows for US$10 - pretty girls get them for free. You can surprise most Nazdar reps by asking them to lookup "21step".

I will tread lightly as I was forced to make an oath to not quibble with the experts whom we are so grateful to have here, but, in 1988, my photographic positives were much more likely to be closer to the same D-min and D-max of these guides than the plethora of media and opaque mediums that we have since experienced. Granted, that many of these combinations were found to be lacking, but they were in use nonetheless.  Even with all of the goodies available, it is a fact of life that in this industry, many work their way up to the good stuff and the right way.

A test done with the user's actual stuff really reflects actual repeatable, verifiable results. Besides, even when the new employee misplaces the guide, you can always find a piece of cardboard.

Oh, and you can still surprise some Ulano reps, or at least distributors, asking them for the free Exposure Calculator Kit they offer.

[RichardGreaves]

A single hit of Epson 1400 yellow ink is UV opaque enough to produce screens. (cyan and magenta are UV transparent)

I just spent 45 minutes looking for the actual film I made with an EPSON 2200 in 2005.  The yellow had terrible UV density, so I ignored it - black had the only stopping power. I will find this film or anybody can send me a small 1" patch on film for me to measure with my Transmission UV densitometer.

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