Printing white ink on dark/colour t-shirts

[steve_c]

Hello everyone,
I had a job done recently and I was charged for two screens when printinfg in white on dark t-shirts.
Is this normal? Is one screen a base and one for making dense and more white?
Like to understand this a bit better if anyone can advise?
Cheers,
Steve

[John G]

Hi Steve, You've answered you own question - base is printed and dried in situe (on the carousel) then the white is printed over the top. You can get away with 1 screen sometimes as you just print the white, dry it then print the white over the top instead of using a base.

Cheers John

[steve_c]

Thanks for quick reply John.
Understand better now.
Cheers,
Steve

[AJLA]

Interesting, unfortunately nearly all my stuff is white text on a black shirt.

[John G]

Try the ultra opaque plastisol, you might get away with one print for thin type text but it won't be as vibrant as the xpres t'shirt vinyl.

When you first screen print white on black it looks great but after drying the black shows through and it looks off white - this is why it needs to hits.

Cheers John

[AJLA]

We were struggling to even make our first possie as it wouldn't dry even after 24 hours until we realised it was printed on the wrong side so now we have one, yes it's black but is it dense enough..won't know till we try it will we but what I want to do next is have one make up on a lazer printer to compare the two. Unforetunately there isn't one that prints onto OHP in the town so i'll have to go into Plymouth next week then we can give the two a trial and see which performs better.

[John G]

If the inkjet posi is black and sharp i'd just use that one - for some reason my laser printer isn't printing as dark a black as it used to but all I do is reduce the time on the lightbox to suit.

Cheers John

[AJLA]

So a really dense black requires more time in the light box?
Will a more dense black produce a better result?

[John G]

A dense black posi will produce better, sharper results and for t shirt work you can over expose the screen so theres less spotting out to do (small pin holes that may appear which need to be blocked out with blue filler). For fine lines, on crap posi's, I under expose which will make the lines better but more spotting out to do.

Its trial and error I'm afraid until you get the right timings - I can go anywhere between 4 and 5 mins, any less and the stencil might start washing away - any more and the stencil is hard to wash out so the light must be penatrating the black on the posi.

Can you upload a pic of your exposure unit - if its lights from above you'll be able to do a test on one screen to obtain the best timings.

Cheers john

[AJLA]

Yep it is a light from above, I will try a get a pic on Monday for you if I can remember to get someone to bring a camera in.

It really all sounds quite daunting to me now but i suppose it's like any new process you take on.