Speaking of Underexposure

[squeegee]

That is a one bad-ass light source Alan.  10k?  Sounds glorious.

I have a 10k as well, Hugh at Richmond told me the bulbs were originally used for landing lights on planes.

[squeegee]

21-28 minutes on a sensitized emulsion?  Gawd, that is a real surprise to me.  Makes me wonder how anything got done way back when our first unit had a 500 watt halogen bulb.

[DouglasGrigar]

21-28 minutes on a sensitized emulsion?  Gawd, that is a real surprise to me.  Makes me wonder how anything got done way back when our first unit had a 500 watt halogen bulb.

Want a full and complete exposure with a thick coating of emulsion... well it takes time with a low power unit...

Did you use newsprint to blott the backs of the stencil back then to keep from having issues with scumming?

The reason underexposure is so common is that the first section of time penetrates the deepest for exposure of the stencil facing the light. As you go deeper less light energy is received by the emulsion as what is in front creates a filter for the emulsion in the back. Deeper you go the longer it takes for the linking to complete.

Most printers were and are just glad it makes it to the threads of the mesh to half-hang-on for its “life” by the “fingertips" in a way.

Note the variables.

Thick coating of emulsion - thicker than you would see most of the time in the wild.

Low power light unit - inexpensive and smaller but with less power (translates to longer time to expose).

Full and complete exposure from front to back 100% linkage, easier to reclaim, will last for thousands on thousands of impressions with plastisol inks.

And If I forgot that was 230 mid thread mesh dyed with the glisten/shine method, rounded edge of the coater (3/2 most common).

[DouglasGrigar]

21-28 minutes on a sensitized emulsion?  Gawd, that is a real surprise to me.  Makes me wonder how anything got done way back when our first unit had a 500 watt halogen bulb.

One of the reasons most do not want to talk about exposure out in the wild, the variables are huge and the weak lights take longer - much longer than most would expect.

I have tested this with all of the most common tube units out there and using the same emulsions the results are all within about 2 min of each other - the only bulbs like this faster are the very thin bulbs packed tighter into the unit.

[jsheridan]

That is a one bad-ass light source Alan.  10k?  Sounds glorious. 

It is glorious, and it's one of those things that I don't appreciate like I should because it's all I've ever known. 

I had the pleasure of using a 10k Richmond back at Logos and IT IS glorious!!

[mk162]

Where do you guys get non-waterproof film?

most of my suppliers stopped carrying it, I think a lot of my problems come from that.

[squeegee]

21-28 minutes on a sensitized emulsion?  Gawd, that is a real surprise to me.  Makes me wonder how anything got done way back when our first unit had a 500 watt halogen bulb.

Did you use newsprint to blott the backs of the stencil back then to keep from having issues with scumming?

You bet.  I'm not sure we knew that was why we were using newspaper though 

I think we used to use Ulano FX88 emulsion back then, we dried the screens in the shop air on shelves wrapped with black plastic!  I'll bet they never fully dried, ever.

Our vacuum blanket was a piece of glass and various large phone books for good measure.  Washout was risky business, you just hoped and prayed the design would not blow off the screen.  We got our Richmond about 15 years ago, I can't even phathom not having it today.

[mk162]

Douglas and Mike, do you guys recommend non-waterproof films for the 3000?  I have a 1K mercury vapor unit.  I noticed that the film doesn't let as much UV through and there is a box where the film sits--no matter how long they are exposed.

[tonypep]

I have a Violux 8002T picked it up used for stupid$$$$. Gotta plug the Douthitt people. Super helpful even though I did'nt buy it from them. Walked me through the wiring and proper set up and programming ( its not rocket science but its a bit tricky if you don't have a manual). Then sent me the link to the manual. Even discovered my screen peeps had it set too far away from the vacum table after talking to Mark. So its not a sexy new totally enclosed unit but for under $1,000 I can shoot three auto screens in just over a minute (diazo emulsion)
I like those #s
tp

[DouglasGrigar]

Douglas and Mike, do you guys recommend non-waterproof films for the 3000?  I have a 1K mercury vapor unit.  I noticed that the film doesn't let as much UV through and there is a box where the film sits--no matter how long they are exposed.

I was neve a big fan of the “waterproof” films with a vac and humid conditions even the waterproof will end up sticking to the stencil and when removed will ruin the positive (so what it is a cost of business), and yes the non-waterproof stuff is available.

Would someone out there who has a supplier let us know who has it in stock?

[Frog]

Two sources that I knew of, Film Source and Screener's Choice have both dropped it. Film Source still has clear film but do not tout it for burning screens but rather for displayed transparencies. Screener's Choice appears to have only WP, so yes, a good question.

[mk162]

It looks like Tech Support carries it.

[ftembroidery]

PerformanceScreenSupply.com advertises both WP and Non-WP, and on the next page of their cyber-catalog they offer a CLEAR ink-jet film and a CLEAR laser film.  I've not dealt with them, so I'm not necessarily "encouraging" anyone to do so.

[ZooCity]

This re-packaged kimoto film from Westar is the best non-wp film I found for the 3000.  The key is that Westar is consistent with it.  They don't just jump from supplier to supplier and re-brand it. 

http://www.westarsolutions.com/vend/westar/westjet.html

Directly opposing my opinion regarding toaster pastries, I think frosted film, even lightly frosted, sucks.  My take on this is that you get the frostiness as a by-product of building up the emulsion side of the film in order to quickly absorb and dry inkjet ink.  "wp" film does a good 'ol job of that for sure and you see a lot less gain out of the printer while still getting adequate d-max with the wp. 

With non-wp film you get that crystal clear but the inks tend to flood up the film a little more to get the opacity or d-max you want.

So to me it's a trade-off between:

A more accurate output with less gain but, alas, light scattering, UV blocking, squeegee side of stencil underexposing, frosty bastard carrier sheets.

Less accurate output from more gain but a pleasantly clear and far less troublesome carrier sheet. 

I want the best properties of both.

Because after all, your print's only as good as your stencil as your film as your art. 

[mk162]

See, I think the opposite, my printer had banding issues until I switched to WP film, I think I get more gain with WP film than non.

I will check Westar.  I think I am going back to non WP.