Hi I'm about to start printing process shirts for the first time as I am constantly turning down work that is full colour. I have some understanding of it I can separate my colours without a rip easy enough in ps and I know a lot about angles but I seem to be having problems with lpi. my image is off a digital camera hi res when I go in to ps to make my halftone seps it asks me what my output is I set it to the same as the image resolution 300 the only reason I do this is because it says so in most tutorials they say to make the output the same as the image res I don't know if this is too high or what exactly it does. The problem is everyone seems to be talking about doing process work with 50 to 55lpi that just seems imposable to me using a basic manual press when I set my lpi to 35 the dot is very small and looks very hard to print on the positives if I print it out at 55lpi they look microscopic and I know I won't be able to keep the dot open when printing does this have something to do with me setting the output to 300 or not. I done a test print last week with the output at 300 and the lpi at 25 it came out alright the problem is the detail looked **** because I was using a low lpi and help would be appreciated.
in Photoshop LPI = frequency.
are you using different screen angles?
I just ran a 250 shirt job full 4 color process with the lpi at 55 and all the screen angles at 22.5
but I use a rip for my film positives....305 mesh screens
ive tried to run this job on 230 mesh screens ..different screen angles ..different lpi...and the above stats is what worked for me..all in all about 24 screens and 24 different films to get the result seen here.its all trial and error until you find what works for you.
I'm relating to the size of the dot not the angles Im saying the dots look very small too small at 55lpi for me to hold does this have something to do with my image res and output
25 & 35lpi are large dots, 300dpi is low for making dots in PS.
At 33lpi each cell is 9x9 pixels and you will therefore have 82 levels of grey, if you use a RIP - even at 720dpi you will have 400 levels of grey or so. At 50lpi you will have only 37 grey levels.
PS isn't great for halftoning.
Get a RIP. 50lpi 230tpi mesh.
It's harder to print process work with a manual press. You will have to be careful with registration.
well the higher the lpi the smaller the halftone dot....thats how you hold detail.....
small to your eye means nice clean image.....plus there will be dot gain when you print onto a t-shirt.....so the image will look darker on the shirt than on the comuter screen...but you can adjust for that in PS.
lpi for process work 
