[mgatechcameroon]

hello there long not bein in the forum, i have been doing alot test in the different types of printing methods and something caught my attention i will like to share, first of all is it true stochastics is the better print method in the textile industry? lets asume yes which i differ abit. the problem is can simulated process separations be converted to stochastic square dots and printed as stochastics thats some i am tryingn right now but wondering if anybody ever tried that.

 

[red514]

is it true stochastics is the better print method in the textile industry?

There is no "best" method, it all depends on the design and desired finished look.

can simulated process separations be converted to stochastic square dots and printed as stochastics.

are you referring to Index separations? this method uses a 'square dot' that are all the same size.

 

[JeridHill]

There is no "best" method, it all depends on the design and desired finished look.

I agree! It's not a one size fits all. I've seen animal prints look awesome with stochastic screening but halftones may look better with portrait photos, etc. It really does depend on your desired look, but also the artwork you are working with.

 

[mgatechcameroon]

hello red 514, yes i mean indexing which is otherwise called stochastic, but my problem was after doing simulated process color seps and having all the spot chanels can one just convert each spot chanel to a bitmap then when the bitmap window opens just convert it to index then gray scale and print the dots out as square dots expose the screens and send them to press. what will it look like anyone ever thoght of trying. thanks guys will love we try that.

 

[red514]

hello red 514, yes i mean indexing which is otherwise called stochastic, but my problem was after doing simulated process color seps and having all the spot chanels can one just convert each spot chanel to a bitmap then when the bitmap window opens just convert it to index then gray scale and print the dots out as square dots expose the screens and send them to press. what will it look like anyone ever thoght of trying. thanks guys will love we try that.

If the simulated process separation is already done, why do you want to convert it to an index sep?

What is the image resolution of your simulated process job, is it equal to the resolution you want to use for Index? simulated process is often done at 300dpi while index is often no higher then 200dpi. You're better off just doing an index separation from the original design image.

i'm not sure what you're trying to achieve by doing this. you could probably recreate what the press would give you using photoshop, think i may try if i have some time.. but i don't think this would work to well.

 

[mgatechcameroon]

okay red514, thanks for replying but this is the thing i know and fully understand your point of view but i am trying to understand what software developers are doing for example the required maximum resolution for doing for doing indexing is 200 dpi which is also good for sim. process color jobs. after separating your job as a sim. process color job and you think its better to index and if converting the gray scale spot chanels to index works on press then what is the need for an indexing software. sorry red514 curiosity and experimenting in screen printing to me has become an obsession. red514 i justy wrote a few actions for doing sim. process seps. and real process seps for darks and light will like you to try it out, whats your email.

 

[red514]

okay red514, thanks for replying but this is the thing i know and fully understand your point of view but i am trying to understand what software developers are doing for example the required maximum resolution for doing for doing indexing is 200 dpi which is also good for sim. process color jobs. after separating your job as a sim. process color job and you think its better to index and if converting the gray scale spot chanels to index works on press then what is the need for an indexing software. sorry red514 curiosity and experimenting in screen printing to me has become an obsession. red514 i justy wrote a few actions for doing sim. process seps. and real process seps for darks and light will like you to try it out, whats your email.

curiosity and experimenting are very good attributes in this industry, one of the only ways to learn and advance your skills.

I'm thinking through the process you are suggesting and i just don't see why you'd want to change the simulated process job into an index. it would still be the same amount of colors (you're converting one halftone screen into a diffusion dithered pattern using only one size dot), the result isn't very clean compared to the halftoned version, why not stick with the halftoned version.

I have done a few sim.process seps that i realized would have been better as a index job so i started the separation all over. When you index from the original cleaned/enhanced art you will get much better results. When i have a chance i will try to render what converting a sim.process to index would look like on press.

 

[mgatechcameroon]

thanks red514. what you are saying is true its just better to index the design from start. but then what if you wanted to index a cmyk or real process job would that not help to just convert the cmyk gray scale images to a difusion dither, do you know theres no way to index a cmyk separation without additional spot colours if there exist in the design, i read offset litho does a real process index without additional spot colors, so how will you handle cmyk job that had to be inexed without additional spot color. thans again red514 its talking to you.

 

[red514]

thanks red514. what you are saying is true its just better to index the design from start. but then what if you wanted to index a cmyk or real process job would that not help to just convert the cmyk gray scale images to a difusion dither, do you know theres no way to index a cmyk separation without additional spot colours if there exist in the design, i read offset litho does a real process index without additional spot colors, so how will you handle cmyk job that had to be inexed without additional spot color. thans again red514 its talking to you.

regarding Lithography printing, i know little to nothing about that process. I really don't know what this even means "real process index without additional spot colors", if you have a link to an article or something i'd be happy to check it out.

i don't understand why you would want to change the CMYK or simulated process separation channels into an index job, the separations are already done, i think i'm missing something.

So i did have a chance to test it out quickly and the first thing that is evident right away is that the stochastic pattern of each channel does not match the others... at all. This is because each channel is being converted to a random stochastic pattern separately, so nothing matches. when doing index, you need to index the image, not the channels.

i don't understand why you would want to change the CMYK or simulated process separation channels into an index job, the separations are already done, i think i'm missing something.
what is your reason for wanting to do this? are you having issues on press with CMYK or simulated process, issues burning halftones?

one of the major differences with CMYK/simulated process VS index is that Index use only 1 size square dot. CMYK/simulated process uses halftone dot patterns, many different sized dots.

 

[PositiveDave]

Stochastic (or FM) dots are just another halftoning option, they are nothing to do with index printing, so there are a few red herrings here.
Stochastic is basically inkjet dither.
With traditional halftones we use the same number of dots in a square inch, hence lpi. The tone is varied by changing the size of the dots. (hence AM - Amplitude Modulated)
With stochastic the size of the dots is always the same (although they eventually join up as the tone gets higher) the tone is varied by changing the number of dots. (hence FM - Frequency Modulated)
Any print CMYK or simulated can be done with stochastic halftoning.
Index prints are not halftoned at all. Each pixel has a 100% coverage of a colour. If you overlay the films for an index print it is totally covered.

 

[mgatechcameroon]

hello there, thanks red514 and a bigger thanks to positivedave i think u just solved my problem. after reading your reply dave i had to so much reading again and aparently stochastic is not indexing which i think thats where i and red514 were stuck, i hate halftone especially when i am doing real process color since most of the time my dots are at 85 lpi on a 165 mesh with enough of open area. well gues red514 understands now why i got drawn into this in the first place, i want square dots of the same size which means if i have to go up to 100 lpi i would not be fighting with 5 percent dots. thanks enery one for your patience.

 

[red514]

i hate halftone especially when i am doing real process color since most of the time my dots are at 85 lpi on a 165 mesh with enough of open area.

that is way too high an lpi for such a low count mesh. the highest i'd recommend to go is 65lpi for 300+ screens and 55lpi for 240-280.


with index, the image resolution controls your output lpi (no rip needed)
from some tests i've done, an index square dot done with an image resolution of 180dpi is almost the same as a 5% halftone dot using 55lpi.
if you have issues capturing a 5% halftone dot at 55lpi you will have the same issues with index.

using lower image dpi gives larger square dots but this also lowers the image clarity. an index job done at 160dpi has more of a stippled look then a 180dpi. using 100dpi, your image will look like a pointillist painting.

 

[red514]

aparently stochastic is not indexing

Stochastic - Definition and More from the Free Merriam-Webster Dictionary

stochastic just means random

here's some good articles on index printing
INDEX SEPARATIONS- PRINTING ADVANTAGES.
Index Separation Method for Screen Printing

 

[mgatechcameroon]

hello red514 was nice reading from you again, its like we have practicaly dofferent readings when it comes to mesh, mesh 165 here for us is in centimeters it seems your mesh specificatiion are in inches. we have always done most of our real proces jobs 165mesh screen which is aproximately 400 or 420 in inches using 85lpi dot. as for stochastics it seems really abit comforting cause if you can burn one dot then you can burn all. well red514 thanks again .

 

[Smalzstein]

you are printing with plastisol on a 165 mesh ?

 

[mgatechcameroon]

hello smalzstein we print with 165 mesh using plastisol and i think its easier than water base inks, do you have problems printing on a 165 mesh with plastisol?

 

[Smalzstein]

Well I'm barely pushing plastisol through 120 thread/cm mesh at 60 lpi halftones What brand of ink do you use ? I think mine's to thick but I'm afraid to add any more reducer, 'cause I've already reached the safety limit. I'm using manukian inks.

 

[red514]

Well I'm barely pushing plastisol through 120 thread/cm mesh at 60 lpi halftones What brand of ink do you use ? I think mine's to thick but I'm afraid to add any more reducer, 'cause I've already reached the safety limit. I'm using manukian inks.

60lpi is abit high for manual printing, try max 55lpi (the 5lpi difference makes a big difference) if you want to make it easier on you i'd go with 45lpi

 

[Smalzstein]

Well I'm printing the 60 on an auto (anatol horizon, pneumatic heads). And yeah and never going higher then 45 on a manual press. I wonder if AC print heads would make a difference in this matter..

 

[tpitman]

What you're referring to is index printing. It uses spot colors like simulated process, but instead of regular halftones using round dots at a specific frequency and angle, it uses square dots that are randomly placed to achieve tints, gradients, and so on.
My only experience with it is outputting an index print through QuikSeps Pro, which has a set of actions to do this. One thing about index printing is that it often takes a lot of colors to get good results. I've also tried a simple white ink sep using indexing, and it came out pretty good. The one multi-color job I tried out of QuikSeps Pro, oddly, produced a moire in the underbase. I changed the dpi to 150 (from 200) and it eliminated it. Index printing is generally assumed to eliminate moire since the dots are random and not in a fixed "grid" like a traditional halftone screen, but as I found out, anything is possible. You can create your own index seps out of Photoshop by essentially assigning spot colors using the color range selection feature to create new channels under Image/Mode/Indexed Color. QuikSeps Pro recommends using 200 dpi as a dot size, and it works really well. The one sep set I did was a 4 spot color job that came out surprising well, except that for some reason, a drop shadow had a lot of blue in it and gave it a sort of exaggerated color look to it. The rest of the image came out great.