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screen printing => General Screen Printing => Topic started by: Dochertyscott on February 14, 2014, 04:57:00 PM

Title: Halftone dot size for gradient
Post by: Dochertyscott on February 14, 2014, 04:57:00 PM
Hey,
So I did this job yesterday for a client which was a basic gradient through a logo.
White base, with a blue gradient and some blue text.
There was a pocket logo @100mm wide and a back print @ 280mm
We used a 55 lpi dot for the blue.
59s white, 120 blue halftone. Mesh. (Metric units)
White p/f/p/f blue p on a manual press.
The end result was perfect but I did have to wipe the blue screen every round (6) in order to keep the dots nice which wasn't ideal. Especially if it had been a large run. (Ended up only being 15 units)
What dot size would Others use for a perfect gradient like so to avoid dot closing in in places?
I don't have a photo of the print as I'm away from the shop but have a look at the client mocks to get what I mean.
http://queenstownscreenprinting.co.nz/qt-conference-video/2014/2/5/pricing-and-mocks (http://queenstownscreenprinting.co.nz/qt-conference-video/2014/2/5/pricing-and-mocks)
Password= video
Title: Re: Halftone dot size for gradient
Post by: blue moon on February 14, 2014, 05:28:47 PM
43T = 110 Threads per inch
54T = 135 Threads per inch
64T = 160 Threads per inch
77T = 190 Threads per inch
90T = 230 Threads per inch
110T = 280 Threads per inch
120T = 305 Threads per inch
140T = 355 Threads per inch
150T = 380 Threads per inch
165T = 420 Threads per inch
Title: Re: Halftone dot size for gradient
Post by: blue moon on February 14, 2014, 05:30:28 PM
Hey,
So I did this job yesterday for a client which was a basic gradient through a logo.
White base, with a blue gradient and some blue text.
There was a pocket logo @100mm wide and a back print @ 280mm
We used a 55 lpi dot for the blue.
59s white, 120 blue halftone. Mesh. (Metric units)
White p/f/p/f blue p on a manual press.
The end result was perfect but I did have to wipe the blue screen every round (6) in order to keep the dots nice which wasn't ideal. Especially if it had been a large run. (Ended up only being 15 units)
What dot size would Others use for a perfect gradient like so to avoid dot closing in in places?
I don't have a photo of the print as I'm away from the shop but have a look at the client mocks to get what I mean.
[url]http://queenstownscreenprinting.co.nz/qt-conference-video/2014/2/5/pricing-and-mocks[/url] ([url]http://queenstownscreenprinting.co.nz/qt-conference-video/2014/2/5/pricing-and-mocks[/url])
Password= video


'not having worked on the manual much, I am only guessing here, but how tight was your 120? If it's loose or you are pushing too hard, you'll stretch the mesh and smear the print.

pierre
Title: Re: Halftone dot size for gradient
Post by: mimosatexas on February 14, 2014, 05:58:24 PM
I find that for doing tiny dots close together on my manual, especially with something like a 305 mesh, I will soft flood like I would with waterbased, so ink covers the stencil but isnt pushed into it, then I do a very fast, very vertical angled stroke with good pressure and the dots are very clean.  Might try adjusting flood and stroke angle and pressure.
Title: Re: Halftone dot size for gradient
Post by: Screened Gear on February 14, 2014, 06:23:02 PM
When you do fill in the dots it is from a hard flood or a too soft of a print.   If you see it starting to fill in just don't flood the next print or two and that should get you back on track. Unless you really over filled and then you will have to clean the screen. Soft flood/ hard print. Do a push stroke and that will make it easier also.
Title: Re: Halftone dot size for gradient
Post by: Dochertyscott on February 14, 2014, 06:30:05 PM
I didn't bother flooding had a nice amount of ink in front of squeegee to try keep it cleaner which helped.
Perhaps it's tension, I'm unsure how tight. I must try and get some shur loc frames.
Probably not idea being a static frame. I'll try a faster print stroke next time.
So 55 lpi as a dot is generally good for gradient? Any larger and it would look a bit obvious for a small pocket logo in my opinion.
Title: Re: Halftone dot size for gradient
Post by: Dochertyscott on February 14, 2014, 06:32:34 PM
Cool, I'll put all these tips to practice and see how I go. In hindsight maybe even more off contact would have helped.
Title: Re: Halftone dot size for gradient
Post by: Screened Gear on February 14, 2014, 06:33:44 PM
I didn't bother flooding had a nice amount of ink in front of squeegee to try keep it cleaner which helped.
Perhaps it's tension, I'm unsure how tight. I must try and get some shur loc frames.
Probably not idea being a static frame. I'll try a faster print stroke next time.
So 55 lpi as a dot is generally good for gradient? Any larger and it would look a bit obvious for a small pocket logo in my opinion.

If your not flooding then its too soft a squeegee, to thin a ink, or not enough downward pressure to keep the ink from going under the gasket of the stencil.

Title: Re: Halftone dot size for gradient
Post by: Frog on February 14, 2014, 06:40:15 PM

So 55 lpi as a dot is generally good for gradient? Any larger and it would look a bit obvious for a small pocket logo in my opinion.

Small areas like this are difficult to make as smooth a transition as you'd generally like because, even though the dots are fairly small, a pocket sized version has fewer dots filling the same space as a full sized version would.
Title: Re: Halftone dot size for gradient
Post by: Dochertyscott on February 14, 2014, 06:59:19 PM
Union mixo inks which I find to be reasonably thick. Squeegee was a 70/90/70 and reasonably new.
I think I need to pay closer attention to mesh tension. Rather than a tap with fingers I should probably get a tension metre. And some retensionables. Especially for when moving into automatic.
I defiantly haven't mastered the push stroke and in most cases do 2 or 3 pulls especially if no base. Other than for halftones. I think that's why I haven't stuck with trying to master the push stroke. When I push I cnt clear the mesh and then there is then no ink in front of the squeegee to go pushing again. Different topic but something I struggle with. Should lift screen and re flood?
Title: Re: Halftone dot size for gradient
Post by: blue moon on February 14, 2014, 07:51:26 PM
mixo is not designed for halftones. My suggestion would be to try the Ultrasoft or even better, the Unimatch series of inks. Halftone printing requires ink that is designed to hold the dot shape rather than flatten out.

pierre
Title: Re: Halftone dot size for gradient
Post by: Dochertyscott on February 14, 2014, 08:19:57 PM
Brilliant, thanks mate.
I love this forum.
Title: Re: Halftone dot size for gradient
Post by: Screened Gear on February 14, 2014, 11:15:03 PM
mixo is not designed for halftones. My suggestion would be to try the Ultrasoft or even better, the Unimatch series of inks. Halftone printing requires ink that is designed to hold the dot shape rather than flatten out.

pierre

Correct me if I am wrong but mixo mixing system makes maxopake inks. If you want ultrasoft inks you mix in 50% softhand base. I believe it's in the union ink pamphlet that you get with the kit.
Title: Re: Halftone dot size for gradient
Post by: Dochertyscott on February 14, 2014, 11:48:40 PM
Hmm, I'll have a look, I know I can buy ultra soft union ink in the pottle but it could be just reduced down.
Is there a difference between using plastisol reducer and soft hand base?
Title: Re: Halftone dot size for gradient
Post by: Screened Gear on February 15, 2014, 12:19:16 AM
Curable reducer and softhand base effect ink differently. Someone else can chime in on the science of it. To make mixo inks ultrasoft inks you have to use 50 percent softhand base. I have mixed it more than 50 % for printing on whites. Curable reducer will make the inks flow easier it breaks down the bonds of the ink. You don't need much. I was told if you use curable reducer and the ink sits for a long time it has the opposite effect. It will make the ink bond and be much harder then if it didn't have the reducer. Only saw that ounce with a white ink that I mixed a lot of reducer into and let it set for months.

Back to you problem. All inks can print halftones. You just need a ink that flows well and can hold its shape after printing. They all can do that on a 2 color job with the halftone screen being second or with flashing between colors. Not sure your experience level but with good technique you should be able to do it.

What press are you using? Does it hold tight registration. On a 120 (305) mesh screens the tension would not matter to much to print a one color on a PFPF white. Tension matters more for registering screen to screen. Even a sloppy screen will print dot on dot to itself. That is if your even printing more than one stroke per shirt with the blue.
Title: Re: Halftone dot size for gradient
Post by: Dochertyscott on February 15, 2014, 12:49:05 AM
Yeah I don't have too many problems with halftones in photos etc at 55 lpi. (Obviously these sorts of prints are more forgiving than a gradient out to nothing) Last actual gradient I did was at a 45 lpi dot and was great. but for this one I wanted it a smaller dot for the picket logo. And caused some issues. I'm reasonably experienced and consider myself a good printer... but always looking for better process' and input. Cheers for all the advice.
Title: Re: Halftone dot size for gradient
Post by: screenxpress on February 15, 2014, 01:56:35 AM
mixo is not designed for halftones. My suggestion would be to try the Ultrasoft or even better, the Unimatch series of inks. Halftone printing requires ink that is designed to hold the dot shape rather than flatten out.

pierre

I know there are a lot of good inks, but I've used Union Ultrasoft for halftones for years including up to 6 colors.  Never have had to clean the back of a screen during a run.  Actually, I find it takes about 5-6 prints for the inks to settle in. 

I'm thinking 55 lpi might be a bit high unless ultra gradient detail needed.  I'm typically at 45 lpi on 165-230 mesh.  And like Andy (Frog) said, a crest print does not have very many dots to work with in the first place to be able to show a decent gradient.
Title: Re: Halftone dot size for gradient
Post by: Dottonedan on February 15, 2014, 06:36:08 PM
When I worked in a prety large shop, we used Union Max and I used that for sim process but added a min of 10% base and up to 20%. It seemed that anything over 20% would dilute the opacity of the inks. If printing on white, no problem, but if printing and combining to create lets say a green fmo a blue and yellow, the yellow would be too thin and not make a good green and the blue would be week so the color would be off.  I like (ONE INK) that can be manipulated as needed. Straight for solid printing and based out for halftone work. so thats why we kept with that.  Adding up to 50% for anything can take away the strength and integrity of the ink. I've been told this by Union but that was about 10 years ago and they may have adjusted their formulation to accomodate.

I'm not even fond of an ultrasoft or even a Unimatch. It's comparably a Rutland M3 and those are (too thin) in my opinion as an artist trying to get specific colors and other effects, but they are popular. I have seen the rise of very thin inks as a staple and to me, it effects your overall output and defines or changes how you handle production and can leave you handicapped. Just my thought.

Another thing I am agaisnt (apparently as an artist) is using big dots on left chest prints. When the back is 55lpi, I often request them to go 60-65 for the front on smaller images to increase more detail and decrease the dot size for better results.

My thought on your print issues is to add to what they have said and also point out another area. The low base white puts down a good heavy coverage of white ink. For me, ( it's too much). It's already a low mesh, so you should be able to get that in one print in most cases, but being on a manual, it's common. You can get there on a manul, but takes more experience and attention to your production like a science.

The top blue is on a 305 mesh with thin coverage of halftones.  The two together seem to be unequally yoked, meaning, they are not a good match together. They can, but not in the best results.
Like the short, fat, bald guy and the tall skinny model. They can get married, but it takes a lot to get them together.

I can see this print like this. HUGE BASE WHITE and a little blue.

First problem I see, is the P/F/P/F/Blue.

For the ink you are using, I would just add in 20% clear base to thin it out just a little, but I may use a higher mesh like a 230 and then do the P/F/P/F/Print blue.  This will be thinner than the last setup and still give you a bright white.



Title: Re: Halftone dot size for gradient
Post by: Dochertyscott on February 16, 2014, 03:13:18 AM
Thanks dan, I was hoping for your input. That's great. I will try this, along with other advice on the next job that's similar.