Optimum exposure time

[OffsetnScreen]

I am wondering how most of you arrived at an optimum exposure time for your screens? I am thinking about ussing this method to arrive at that magic number. I am first going to create several one inch by one inch boxes in Photoshop and create different screen halftone values for those boxes and fill them, then output them at 1200 dpi, 40line screen round dots, and lay the transparency onto the screen with the rest of the screen masked out. Make the exposure, move the mask and transparency down, mask out what I just burned, make another test exposure, repeat the process a few times and go wash out the screen and see which position washes out the best to determine the best exposure. Is this kinda like how its done? This is the method for determining the proper exposure for film so I am figuring it should work for screens. Any ideas will be appreciated...peace

[Saati]

http://www.youtube.com/watch?v=5UPRYQY7P2M

this is the most accurate way of doing the job.

[OffsetnScreen]

I watched the video on proper exposure. I came across a Stouffer T-2115 stransmission step wedge numbered to 21 steps over by the Nuarc for plates. Is this the same step guide that is mentioned? Will "11" yeild my best results on the Stouffer gauge? thanks in advance. Now I have to make up my mind whether to use the Nuarc or the 500watt entry level light source. I got my new fresh piece of clear heavy glass to hold my vellums flat...

[Saati]

I watched the video on proper exposure. I came across a Stouffer T-2115 stransmission step wedge numbered to 21 steps over by the Nuarc for plates. Is this the same step guide that is mentioned? Will "11" yeild my best results on the Stouffer gauge? thanks in advance. Now I have to make up my mind whether to use the Nuarc or the 500watt entry level light source. I got my new fresh piece of clear heavy glass to hold my vellums flat...

It is the same transmission guide. we just put our name on the one we sell. But what you are looking for is where step 7 is solid (wont let ink pass through) 8-21 will allow ink to pass through. Step 11 will be WAAAAAY over exposed to hold any kind of detail and more than likely will not develop at all using velums since they are not nearly opaque enough.

[OffsetnScreen]

Thanks, I should have read that post yesterday. Youre correct...I was having trouble with an 11 at 6.5 units using the 26-1k nuarc...I've cleaned the screens, theyre drying, I'll recoat them tonight since my darkroom isnt finished and try again tomorrow...I think the 7 showed solid around 4 units which is a fairly quick burn. I am still considering trying to use the 500k halogen work lamp thing if i have more problems with the image.....thanks.

[Saati]

Thanks, I should have read that post yesterday. Youre correct...I was having trouble with an 11 at 6.5 units using the 26-1k nuarc...I've cleaned the screens, theyre drying, I'll recoat them tonight since my darkroom isnt finished and try again tomorrow...I think the 7 showed solid around 4 units which is a fairly quick burn. I am still considering trying to use the 500k halogen work lamp thing if i have more problems with the image.....thanks.

4 units sounds fast for sure.... almost not controlable by the integrator. how long is that in seconds. if less than 10 seconds then I would see if you can move the lamp further away or see if there is a way to turn down the intensity...Some lamps have that option.