Safe Lights

[Rick Roth]

I have been on various threads with people spending what I consider an inordinate amount of time debating whether you need safelights in your screen room. I just had the luck to visit the KIWO main manufacturing facility in Wiesloch Germany. It is the most high tech, clean, efficient factory I have ever visited.

They had safe lights, safe light covers on lights, and safe light films over windows wherever they were working with emulsions.

I asked and was told it was necessary, and also then got the answer I always have given as well, which was, "why would anyone care, the covers are so inexpensive anyway."

Look for my post on theinkkitchen.com soon on my visit to KIWO, if you are at all a screenprinting geek like me I think  you will find it fascinating, I have a boatload of photos. The posts will go up in the next two weeks, as well as a long one about MHM which I also visited.

[Underbase37]

I would agree...but side note. Our dark room uses a shower certain of the king & a oversized tie dye tapestry  for a door that leaves people to not close it correctly & daylight to come in on occasion & I have never had problems....all the screens are in a drying cabinet or closed storage though.
Oh & luuuuckyyyy;D

Murphy37

[Frog]

This is one of those issues that falls under the category "What I seem to have gotten away with for as long as I can remember vs. the optimal way that will help assure success, especially when I step up my game"

[ScreenFoo]

I personally think the real issue for most is just keeping the light off wet emulsion when it's coated on screens, but it stands to reason less light contamination across the board equals a better chance of success, especially on challenging work.

It would be a blast checking out their operation, looking forward to checking out those pics. 

I've always been impressed with Kiwo's resources on the web, although Ulano has more than a few great articles available as well.

[tpitman]

The only time I've ever gotten light contamination was using Saati Textil PV and turning on the fluorescent light behind my washout sink before I'd wet the screen down. I coat my screens under a bug bulb, but carry the wet screens to my dry box under overhead fluorescents, and my exposed screen under the same bulbs to my washout sink, without any problems. I think distance from any artificial room lighting as well as time is the determinant. That's what happens in your exposure unit, too.

[jsheridan]

looking forward to it Rick as I really don't like the idea of spending $2-300 on LED bulbs for the screen room if i can just get really good sleeves that block the correct UV waves for 1/4 of the cost.

[Rick Roth]

I just checked and found 4 ft yellow and amber covers for fluorescent bulbs for about $5 each. There are too many variables that are not controllable in screenprinting, so part of good printing is to eliminate all the ones you can. For that price I would not even take the chance of light contamination. I have printed thousands of shirts in my life with screens made with a pie plate/150 watt bulb "exposure unit." I would not recommend that, nor recommend a dark room to be full of light. If the emulsion is photo emulsion, it is photo sensitive. I doubt anyone on this thread has the equipment to determine if halftone printing is effected by emulsion being exposed to light before coating or during coating. More importantly, are the results noticeable? Rarely do prints match each other and there are too many variables (humidity, age of materials, temperature, age of squeegees, …) to determine whether safelights or not were the cause. Spend the $5 per bulb is what I would say. If you are even considering saving money that way, consider business lessons or sales lessons instead of thinking about this.

[Binkspot]

For me at least it's not about the cost of the sleeves or bulbs but working under the yellow light, given a choice if possible I would rather work under "day light" conditions. 

[Underbase37]

That's funny I know a guy that prefers the yellow light....old habits I guess.

Murphy37

[ScreenFoo]

I have a white light in the screen room for cleaning time, as well as checking to make sure diazo is completely mixed.  Sure comes in handy.

[jsheridan]

I just checked and found 4 ft yellow and amber covers for fluorescent bulbs for about $5 each.

I've got the sleeves from UV process. The amber sleeves block up to 500nm where the clear only block up to 400nm.

I have the ambers on the bulbs closest to the screen racks and the clear on the bulbs over the direct to screen.

BOTH sets of sleeves have failed the coin test..

BUT..

We have clear plexiglass so you can see into the screen room, it blocks 99.9 % of UV light and has PASSED the coin test.

Solution.. box in the overhead bulbs with the same plexi on the windows and call it a day.

[Sbrem]

I've been using sleeves for about 30- 35 years. Dirt cheap, just do it is my attitude. We also have a fair amount of daylight leaking in, but we have a screen dryer and cabinets for storage, so it's just not an issue, they aren't out in the light long enough to have any ill effects, not that it couldn't happen, poop does after all.

Steve

[alan802]

I put in the sleeves on our flouro bulbs in the dark room and removed this "amber sheet thingy" that someone had put over the clear cover and it turned our dark room into a bright, light safe room where before it was dark and extremely hard to see everything you were doing.  I wonder all the time who was the one that was in charge of setting up the screen printing building as it was before I started here.

[TCT]

Hey I have posted this link before, but seems fitting now also maybe. I have found a great deal on UV blocking sleeves here-

 http://uvps.com/product.asp?code=FILTER+++I