Author Topic: How bright is your Dark Room?  (Read 7677 times)

Offline squeegee

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Re: How bright is your Dark Room?
« Reply #15 on: November 02, 2011, 08:15:59 PM »
I was told by a Ulano tech that the clear sleeves even up to 400nm UV protection are not good enough, so I went with the amber sleeves which block more like 525nm per Ulano's recommendation, not much price difference between them, and I don't mind working in the yellow light.


Offline screenxpress

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Re: How bright is your Dark Room?
« Reply #16 on: November 02, 2011, 08:49:08 PM »
Ah, the old bug light story, eh?  It's been over 4 years since I had a bug light in operation. 

My suggestion is just coat your screens under florescent light and let dry in the dark like a drying cabinet or a covered screen rack.  When it's time to prepare one, just pull out a screen under normal room lighting, tape on the film and expose. 

The only story I ever heard of room lighting exposing was turning on the light behind a washout sink before wetting the screen had a negative effect.  Mine are florescent behind my washout sink so must have been some robust suckers. 

I work under normal room (florescent) light and stay away from old man sun.  You can't run fast enough to shade to stop the sun from exposing.  Well maybe if you were Superman.   :)
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Offline Fresh Baked Printing

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Re: How bright is your Dark Room?
« Reply #17 on: November 02, 2011, 11:06:44 PM »
Ah, the old bug light story, eh?  It's been over 4 years since I had a bug light in operation. 
My suggestion is just coat your screens under florescent light and let dry in the dark like a drying cabinet or a covered screen rack.  When it's time to prepare one, just pull out a screen under normal room lighting, tape on the film and expose. 
The only story I ever heard of room lighting exposing was turning on the light behind a washout sink before wetting the screen had a negative effect.  Mine are florescent behind my washout sink so must have been some robust suckers. 
I work under normal room (florescent) light and stay away from old man sun.  You can't run fast enough to shade to stop the sun from exposing.  Well maybe if you were Superman.   :)

Even easier. I wonder if all products behave the same under florescent light?
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Offline 3Deep

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Re: How bright is your Dark Room?
« Reply #18 on: November 02, 2011, 11:32:51 PM »
I use both lights  florescent lights and the yellow bug lights not at the same time though in my dark room, never had any problems with the screen being preexposed, then I wash then out under full florescent shop lights heck I,ve even left one in the washout for about 15 mintues and finished it up with no problem just a little harder rinse.

Darryl
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Offline Gilligan

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Re: How bright is your Dark Room?
« Reply #19 on: November 02, 2011, 11:36:31 PM »
Look at it this way, they say you need a metal halide light to properly expose screens.  Not a High Pressure Sodium bulb.  Which both are used in growing plants and taking care of animals that need UV spectrum light.

So if that isn't enough UV then "non-UV" lights certainly shouldn't be "enough".

Now... the problem is... what is "enough".

Offline tpitman

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Re: How bright is your Dark Room?
« Reply #20 on: November 03, 2011, 07:23:39 AM »
The only story I ever heard of room lighting exposing was turning on the light behind a washout sink before wetting the screen had a negative effect.

Uhh, I think that was me, Wayne. I was using Saati's TextilPV, which I thought was the best plastisol emulsion I'd tried, especially for the price compared to QTX.
Anyway, I deduced that the backlight was the issue, since that was the only time I'd ever done that, and the only time I've ever had an issue washing out a stencil. I can't say the bulb was particularly potent, but it might very well be the emulsion was that fast. Currently I carry coated screens, wet or dry, through my garage with 4 sets of fluorescent shop lights and a window and a door open and have no trouble. I do use a bug light in my exposure room and when I'm washing out, but a light-tight room with a 15w red darkroom light of the variety used with ortho film is way overkill. I've read of folks using regular fluorescents in an exposure unit so I guess there must be a little UV light coming out, but I think unless you're holding a screen close to a bulb, exposure is pretty unlikely. No one seems to really have any trouble with ceiling-mounted fixtures.
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Offline T Shirt1

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Re: How bright is your Dark Room?
« Reply #21 on: November 03, 2011, 07:38:20 AM »
10 x 16 room for exposure unit (and spare), washout sink, screen dryer and a table.  Inside painted black with 3 red lights on the ceiling and two more over the washout sink - regular flourescents overhead are on separate switch from the reds.  Also a red light over the dark room door to keep people from running in and out when we have film out.
steve

Offline Denis Kolar

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Re: How bright is your Dark Room?
« Reply #22 on: November 03, 2011, 08:03:52 AM »
I work from my basement, and I do not have separate dark room.
I work in printing company and when we got rid of our dark room (went direct to plate) we hat plenty of UV safe bulbs left.
Of course, some of those ended up in my possession :) Now in my basement, I had the basement window blocked to prevent light from coming in, I turn off regular lights and I turn on fixture with 2 UV safe tubes and also I have 2 bug repel bulbs that I have over the press and in front of the washout booth.
When the screen is washed out, I have the backlight turned off until I'm almost done washing the screen. Then, I turn on the backlight and I do the final and fine detail with the light turned on.
A lot of turning on and off in my basement :)

Offline IntegrityShirts

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Re: How bright is your Dark Room?
« Reply #23 on: November 03, 2011, 08:53:45 AM »
When I worked out of my garage my pressure washed blew up so I had no water in my washout unit. I had a job that I had to get done so I just grabbed the screen and ran outside in a shaded spot to wash it out with the hose and I got nothing. It would not wash out anything. I could see the design for about 15 seconds then that even went away. I figured out if i took a spray bottle and wet the screen really good let it sit for about 30 seconds I could get outside and wash it out with out to much trouble. (so glad I don't have to do that again) I use Aquasol HV. Its great stuff but you have to have your times right. 25 seconds on my photo sharp exposure unit with 10% OEM.

I use Aquasol HV and had a similar experience.  It was a morning when the sunlight was casting a direct vertical stream of light in my washout booth that hit a screen I was washing.  It left me with a hardened vertical stripe through the whole design.  Needless to say with Aquasol I avoid direct sunlight like a vampire.  That being said, I align my film to my fpu out in the shop, grab a screen from the dark room, stick it and walk to the exposure unit in regular shop fluorescent light, then to the backlit washout booth and wash out and never had any issues.  I also gang designs on screens so I align one film, stick it, remove the screen and lean it against my leg while I position and tape the other film, stick that one, then expose.

I don't have any lights in my dark room, I coat screens just outside the door on the floor then rack them.  I use ambient shop light to pick the right mesh while I'm in there with the door open.

Offline prozyan

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Re: How bright is your Dark Room?
« Reply #24 on: November 03, 2011, 12:46:04 PM »
My "dark" room is actually pretty damn bright.  Four 15w CFLs in it. 

Of course, I'm not trying to burn 3% 65lpi dots either, so a little light pollution doesn't hurt me a bit.
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