Starlight Exposure Results

[jvanick]

All of us that are using the Starlight units, here's a place to compare our emulsion testing results.

These are just exposure #'s, I haven't tried the on press yet, but will post results when I do:

Nova+Diazo:

156 mesh: 1:30 .. probably over cooking a bit, but no loss in detail, and no problems even washing out the illustrator 'info' text at the top of the screen.

200 mesh: 52 seconds... this seems like the perfect # to wash out halftones down to a 45lpi-2%

300 mesh: 30 seconds... might need to do some more dialing in tho, the 55lpi-1% halftones are mostly closed, although they appear to be landing on the mesh itself and not the 'holes'.

I didn't have enough coated Nova without diazo screens to play, so I'm waiting on those to dry overnight before trying to shoot them.  I'll also coat some screens with SP-1400 to try them.

[Homer]

making a spread sheet over the next few days and then I'll update, I just can't remember off the top of my head. I'm using CCI TX-Discharge PP with and without Diazo and HXT emulsion just to try out -thanks Mike-, coating for discharge 1/1 sharp edge and glisten for plastisol, I think we're 2/1 and 3/2 on higher mesh....

we have shot a total of 20ish screens so far, everything from 110 S mesh thick stencils to 65 LPI and not a single complaint. I'll post up when I have my chart made..times have been from 8 seconds up t 30 with diazo so far so I think we'll land around there.

[244]

All of us that are using the Starlight units, here's a place to compare our emulsion testing results.

These are just exposure #'s, I haven't tried the on press yet, but will post results when I do:

Nova+Diazo:

156 mesh: 1:30 .. probably over cooking a bit, but no loss in detail, and no problems even washing out the illustrator 'info' text at the top of the screen.

200 mesh: 52 seconds... this seems like the perfect # to wash out halftones down to a 45lpi-2%

300 mesh: 30 seconds... might need to do some more dialing in tho, the 55lpi-1% halftones are mostly closed, although they appear to be landing on the mesh itself and not the 'holes'.

I didn't have enough coated Nova without diazo screens to play, so I'm waiting on those to dry overnight before trying to shoot them.  I'll also coat some screens with SP-1400 to try them.

just a FYI for new Starlight owners as we see the times and emulsions being stated the times are a little longer than our test. This may be due to us using our coater and the emulsion thickness may be a variable. I will have some brands of emulsion, mesh counts,different colors of mesh, and coats posted for some comparisons. Your times may vary but it will be a good starting point.

[jvanick]

I should mention that all of our screens are coated with the round edge, 2 strokes (one right after the other) on the shirt side, 1 stroke on the squeegee side. 

However, as I mentioned in the other starlight thread, I very likely could be overcooking the screens... it seems that even when I am over cooking, there's no ill-effects, or at least none I can determine... (all the detail is still there).  Since we do a fair number of discharge shirts, I'd much rather over cook... I suppose I can to start targeting downwards... but really at the end of the day for us, we're exposing screens faster than we can rinse them out, so no big deal.

however, on the 200 mesh screens, below 45 seconds and i can certainly start to see the 'haze' of film, vs outside the areas of the film.

[244]

I should mention that all of our screens are coated with the round edge, 2 strokes (one right after the other) on the shirt side, 1 stroke on the squeegee side. 

However, as I mentioned in the other starlight thread, I very likely could be overcooking the screens... it seems that even when I am over cooking, there's no ill-effects, or at least none I can determine... (all the detail is still there).  Since we do a fair number of discharge shirts, I'd much rather over cook... I suppose I can to start targeting downwards... but really at the end of the day for us, we're exposing screens faster than we can rinse them out, so no big deal.

however, on the 200 mesh screens, below 45 seconds and i can certainly start to see the 'haze' of film, vs outside the areas of the film.

is this on yellow or white mesh? White is way faster than yellow. Just a FYI .

[Homer]

JV, are you using WP film? we have yet to see that outline of the films, we did have it with our old flo tube unit.

for us it seems anything over 30 seconds may be overkill...but I will put one in at 45 and 60 seconds or so just to see what happens. We ran 100 piece CCI D-white job on a screen coated for plastiosol, no diazo, 2/1 round edge, 160 white mesh, - not a single issue. 100 is not a big run but the emulsion didn't show any signs of wear...no pink in the ink like we used to get with the flo tubes.

[jvanick]

yellow 200 mesh.  and yes, it's Fixxons WP film...

this could just be the Nova+Diazo emulsion?

I haven't tried the SP-1400 yet to have a comparison, or the Nova without diazo.

[patfinn]

Fellas
Here are generic times that we found. We coated screens 1/2 sharp 2/2 round with different emulsions to get a range of times.
These times are VERY GENERIC  and can be different from shop to shop depending on certain variables.

Photopolymers
High mesh 3-5 sec.
Low mesh 6-10 sec

Diazo / dual cures
High mesh 20-38 sec
Low mesh 50-75

These are meant for starting points, I suggest you use an exposure calculator to get exact times.
Have a great weekend

[jvanick]

I got my Stouffer strip back from a friend and did some more testing today...

Appears that I was WAY over cooking (which you guys were all pointing to

300 mesh -- 18 seconds to 7 full steps
200 mesh -- 28 seconds to 7 full steps

on the 200 mesh, I could definitely see the outline of the film.  Not so much on the 300.

[Sbrem]

When it comes to exposure tests, I tend to prefer step exposures to using an exposure calculator. It just seems like I'm testing what I'm doing instead of following someone else's numbers, though the concept is quite sound. I think for this piece of equipment, I would use 10 second exposure intervals, then narrow it down from there after determining which of the 10 second intervals is best...

Steve

Needless to say, I don't have one, but I have made hundreds of exposure tests over the years...