black opacity and photoshop vs illy vs indesign

[StuJohnston]

I have basically only used vectors for my screens up to this point, now that I am getting to the point that I am considering doing it for money, I thought it would be a good idea to start working with half tones.

My workflow is illustrator->RIP at the moment. The rip isn't a screenprinting RIP, it's built to imitate offset for prepress work, though it prints much better than the regular driver for my printer and gets darker blacks. When I went to do a half tone, I used the willflex EasyArt action (I think that I should try it on my own, the curves action was a little rough.) I made a 55lpi halftone, zoomed in, looked fine, then printed to the rip. The positive wasn't nearly as opaque as I was used to. I placed that file and some higher lpi photos into illustrator, printed and voila! They were magically darker, like I expected in the first place. The only issue was that the halftones didn't look quite right over 65lpi. I remembered that a friend telling me that he puts everything he want to print into indesign to print no matter the file type. So I tried that, the half tones looked better yet! Any ideas why photoshop wouldn't print a BMP file totally black?

The outcome was that I was able to hold 65lpi on a 230 screen. I think I could do better with a little more exposure time. Next up is a 305 screen test.

[Dottonedan]

 See a flaw so far. You are miss understanding the term ( able to hold a 65lpi on a 230).
It's not mechanically possible.  Yes, you can burn a 65lpi on a 230 mesh, but when you really look at it. You are probably filling in at the shadow tone of 85% and losing all the dots under 10-15% that means you really are not holding a 65 lpi on a 230. The best halftone that allows you to hold all the detail is a 45lpi on 230. 

I get that from dividing my mesh by 4. 230 divided by 4 = 57.5lpi (round down to 55)
Many divide by 4.5.  = 51lpi rounded to 50

To assure you will be holdng the best gradation to the smallest dot possible, I increase my chances by using 5. (230 mesh divided by 5) = 46lpi  So with that said, if I want to use a 55lpi, I would use a higher mesh like 305.

[Denis Kolar]

How good is your file. You should have files that are at least 200 dpi when they are at 100% for screen printing. Preferably 300 dpi.

Also, as Dan said, no need for 65 dpi for manual printing. If you want to try, limit yourself to 55 at the max.
I did have some screens burned at 55 lpi on 230 mesh, printed good, but it gained "a bit" 

Also, it depends on a quality of your exposure unit and your emulsion.

For now, stick to 45-50 until you get better. I'm a newbie too, and I learned that you do not want and try to overachieve at the beginning. Try slowly and build your knowledge.

Also, when you get your seps in Photoshop, you can export each color as a separate file, and If you get better prints from Illy, place those files in Illustrator and print from there.

Good Luck

[Dottonedan]

Pertaining to the ink on your film and the difference coming from photoshop, that can be the color settings in your ink setup. You could have a color setting preference that takes out a % of ink from each screen. Illy does not do that.

Photoshop,
TOP MENU BAR, EDIT, COLOR SETTINGS

Under working space, Go to CMYK, and scroll up to CUSTOM at the top.  Now, in your options at the bottom, check out the BLACK GENERATION options. Change each one and notice how they affect the GRAY RAMP window.  Also note, the TOTAL INK LIMIT.  I keep mine around 270 max. Off set pritners keep in near 250-26

What these setting do, is change the amount of CMYK % doing down to build a color. How that affects your film prints (out of photoshop) is because whatever it's set at, might be too weak. Lets say your total ink limit might be set at 240 or so. This is all CMY colors combined will not reach more than 240%.

Your film printer might use ALL of it's original colors (and actually prints CMYK+ those other colors, like light Cyan etc. So THIS setting, since it's a CMYK setting, would affect your total ink output (on film).  Get me?

[StuJohnston]

This is flatstock, so I am hoping that I can be able to get higher dpi/lpi. Forgive me for being ignorant of plastisol or other garment printing methods, but I am assuming that there is significant dot gain with textiles. You're probably right that the print isn't really as good as I think it is.

Maybe I am doing it wrong, but 45lpi dots look gigantic and way below the capability of 230. I haven't compared to the original to the print yet, I was sort of excited that it looked good as far as I could see. I will compare right after I finish writing this.

The odd thing about that color adjustment is that I have it synchronized across all of my adobe programs. At least I thought I did. This might explain why my black and white photos print different than I expect. The ink limit was at 300% already, but I upped the black output and I will see what happens.

As for ink limit, I have a setting for that in my RIP as well as an option to make 'rich' black. I have that turned off as it tends to result in a brown on the transparencies. Shouldn't allowing the printer to manage color remove the limit on black ink?

I recently got a semi auto press, so I hope that I can get better than 45lpi. I think I will go and pick up a 355 screen just to see what that looks like. Thanks for the help Dan! Now to go look at the positive, screen and print with a loupe.

In case this makes any difference, I used an Olec al-53 (or 51, one is for the euro market iirc but I can't remember which) with kiwo poly plus S for the screen and nazdar 9700 and a 80 duro squeegee for the print on calendered cover stock.

[Dottonedan]

author=StuJohnston link=topic=3492.msg38033#msg38033 date=1334191188]
This is flatstock, so I am hoping that I can be able to get higher dpi/lpi. Forgive me for being ignorant of plastisol or other garment printing methods, but I am assuming that there is significant dot gain with textiles. True,  we do, but your issue (begins) with using the correct mesh and halftone output.  That is is the same on flat stock as it is on tees. In fact, you will see is more so on flat stock as the garment textures helps hide the "poor results" more than a flat smooth surface.

Maybe I am doing it wrong, but 45lpi dots look gigantic

  They are,  I do not prefer them myself so I would go up to a higher mesh and use the next line screen up (that fits on that high mesh)

and 45lpi being way below the capability of 230.

  It's not. It's PERFECT for 45lpi. It's THE best choice when trying to hold all dots.
I haven't compared to the original to the print yet, I was sort of excited that it looked good as far as I could see. I will compare right after I finish writing this.  It will look very smooth and soft (in the areas of 7-85% or so. like crap in the other areas.

The odd thing about that color adjustment is that I have it synchronized across all of my adobe programs. At least I thought I did. This might explain why my black and white photos print different than I expect.

  Yes.  You also have another preference setting in Illy. Check preferences. That takes your CMYK black to either a RICH black or a SPOT COLOR black (by taking out all CMY from the black).

The ink limit was at 300% already, but I upped the black output and I will see what happens.

  Should be no higher than 270-280 max even on flat stock.

As for ink limit, I have a setting for that in my RIP as well as an option to make 'rich' black. I have that turned off as it tends to result in a brown on the transparencies.

That brown is fine, as long as it is OPAQUE (hold it up to the light to see) and in order for it to become more opaque, it needs a strong % of each of the CMYK to make up a RICH black.

Shouldn't allowing the printer to manage color remove the limit on black ink?

I'm not sure, it seems liek you don't have all programs using the same settings along with your RIP. Seems to be counteracting with each other.