Ghosting/shadow on print

[StuJohnston]

I get it, from you guy's perspective I'm doing things the hard way.  But you guys forget how intimidating this stuff was when you first started.

Now, the reason I use vinyl is, you mentioned like 3-4 pieces of gear/processes that need to be done to use emulsion/cap film.  Each of those have a process to themselves.  First you got to prep the screen.  Then you have to coat the screen... this is intimidating in itself... though less so after I watched my buddy's guys coat a couple screens first hand. 

…and vinyl has its own process. Maybe it's ok to use vinyl for short runs, but what happens when you get an order for 200+? I can't imagine that it would be a good idea to learn how to use emulsion from scratch when you get a larger order.

Still I worry about 1:1 coating (I think I would rather do 2:1 *shrug* ).  Then you got to dry them (no big deal)... then you have to expose them.  I'm scientific... sun just isn't a consistent source where I am.  I want to "set it and forget it" like a rotisserie oven on tv.   So that means I need an exposure unit.  I'm getting close here because I saw where someone is successfully using a vacuum storage bag to get a tight film to mesh seal.... Oh, speaking of... I have to make sure I can output nice good dark films (and buy them and hope I get ones that work... I think I'm gonna get Fixxons for my WF1100 Pigment ink printer).  Then I have to get my exposure times right so everything washes out properly.

To be honest, 1:1 coating is ok for short runs, it might be even ok for long runs. So long as the exposure is good and the emulsion is tough enough. But a 2:1 or 2:2 is what I like to use. I started with a 1:1 sharp side coating and it worked ok, but as my technique improved, I was able to get more consistent coating. Combined with a nice exposure unit, I got nice sharp, thick stencils. Speaking of improved technique, it might have taken me five screens to get good at 1:1, I only continued that until I got a 1000 watt metal halide and moved on to thicker coatings.

I really think that you are making a bigger deal out of this than it really is. Just go to your supplier and tell them what kind of ink you are using and ask if they will give you a quart sample of the appropriate emulsion. It isn't recommended, but you could even use your squeegee to coat the screen, that's what I did before I got a scoop coater. Some even use a credit card! They should also have samples of emulsion remover and degreaser.

Come to think of it, ask for the sample ulano exposure calculator. It will go a long way toward helping you dial in your exposure. If they don't have the sample, the calculators that they sell should only be $50 or so dollars and look alot more comprehensive than the ulano sample. It's possible to get in the ball park by guessing, but you would go through much less emulsion with a calculator. I forgot about the manual step wedge method, but the sample would be easier.

Trust me... working the squeegee and curing has ENOUGH things to learn about.  I just needed to get my squeegee wet and get some printing going on.  Then I can start adding other parts of the puzzle together later.

Basically I am a garage printer doing this as a side gig that is looking to make it into something bigger... but as I'm coming up to that pace and learning the ropes... for me, the best thing is taking it slow and one step at a time. 

Let's put it this way... I bought my first screens in Feb-2010... I just printed my first job last week!  I didn't even own a squeegee or ink until a week before that!

 To be fair, I have never tried to use vinyl for stencil material, so I can't say for certain that it is the source of all your troubles, but at least try using the traditional photo stencil method. Could you ask your buddy to allow you to use his equipment to coat and expose a screen or two? What if using emulsion made it easier to pull the squeegee and get clean prints? If you are looking to make it into something bigger, you will move on to some sort of photostencil. How much detail can you get out of a vinyl cutter anyway? Will it do an 88lpi stencil?

I am also a garage printer that is currently low volume, but I am taking this opportunity to learn as much as I can about the process so my life will be easier when I do get a large and complicated job. I had done some printing before this, but I have just started in earnest last june. In earnest meaning that I am trying to do it right the first time. Before that I was coating with a squeegee, exposing with a 150w incandescent and printing with a helper holding down the screen.

As for stencil versus emulsion. I swear that my screens feel tighter with a stencil in. At least it should make it more difficult for a low tension mesh to wrinkle I would imagine. Of course, this depends on the emulsion. I have some ulano that feels like rubber and kiwo that feels like hard plastic.

Another thought, Have you  degreased and or abraded your mesh? Doing so might help the vinyl stick better.

I know this is a ton o' words and all, but I noticed that you said something like, "That's easy for you to say, but…" So I wanted to put in my 2 cents as a relative beginner to try to explain that it isn't as difficult as you may think. That isn't to say that I found it intuitive, far from it, but I had the help of the search function on multiple screen printing boards and the members themselves when I could find it in the search. Also, going to a brick and motar supplier has helped in many other ways. Whenever I tell them that I want to buy something that I haven't bought before, they check to see if they have a sample and order it if they don't have it. If it weren't for the samples, I would still be using the same emulsion that I started with, which is terrible in comparison to what I am using now for what I print.

Come to think of it, I can't recommend going to a brick and mortar store enough. I realize that they vary in level of customer service, but they can help you in ways that are difficult through online retailers. Even if you are going through a local supplier, try to ask as many questions as possible and they will probably try to help with info and samples if you need a different product. The first time I asked a question to the sales guy at my local Midwest, he got on the phone with Nazdar! My jaw dropped. He has even offered to come out to visit my shop, though I don't think I will take him up on that until I want to buy equipment from them. I figure that they want me to succeed so I will keep buying more and more stuff, lol. So far, it's working like a charm.

Just in case the pile wasn't big enough, here is a picture of my first exposure with kiwo poly plus on 110T with a 1000W MH using the ulano ND filter over a film that I printed. I have since gotten it much more dialed in, but I was pretty excited about this when it happened.


IMG_3513 by StuJohnston, on Flickr

full size here, http://www.flickr.com/photos/31102165@N08/6007156129/#sizes/o/in/photostream/

If you look through my stream, you will see other process photos, but there is a fair amount of work done by printers at my shop that are even more novice than I am. Also it is much more flatstock oriented, but the screenmaking principles are the same.

Uh oh, another idea. Wouldn't you still have to use haze remover with a vinyl stencil? That is probably the worst part about screenmaking. Also, wouldn't the vinyl leave behind some of the adhesive? I had better submit this soon before I think of more!

[Frog]

Another thought, Have you  degreased and or abraded your mesh? Doing so might help the vinyl stick better.

No, no, a thousand times no!

This is the one part of your otherwise helpful post that is dated and incorrect by today's findings.

Even at it's height of use, abrading was really only designed for use with cap film or other film type stencils. (never needed with proper application of emulsion which more encapsulates the mesh)
At any rate, it was discovered that more damage was done to the mesh itself, leading to premature mesh failure, or tiny particles of abrader or diy household scouring powders trapped in the thread overlaps)

I started with real silk, and never did a thing to it with the stencils of the time.
Synthetics came in to stand up to the chemicals needed to remove the newer stencil materials, and if I remember correctly, some were nylon which was really slick. Perhaps that's where this then-common practice originated.

Somewhere, maybe from Kiwo or Autotype, there are micro photographs of mesh damaged in this way. I also believe that Douglas Grigar had an article on this, but can't locate it.

[StuJohnston]

Ok, I will cop to giving some bad advice. I have never personally abraded any screens, but I figured that the vinyl would have a hard time holding on to begin with. I should also mention that some companies that I can't recall the names of have old videos that must have been made in the eighties that have been uploaded to youtube where they use products they sold to abrade new mesh.

No degreaser?

I am pretty sure I saw the article you are talking about in the articles on Kiwo's site.

[Gilligan]

Absolutely plan on learning the process.  Trying to figure out what I need to get from my supplier besides a scoop coater (didn't have the size I wanted when he delivered last time.  Which brings me to a small point, they are 2 hours away so I can't really just drop in and ask questions.

I appreciate all the advice though and I will be doing all of these things soon!

The vinyl sticks pretty well to the shirt side.  Yes the adhesive causes issues but you just have to wash out the screen as SOON as you are finish or it gets real goopy... either way still no fun.

And yes there is still a dehaze process.

[Frog]

Ok, I will cop to giving some bad advice. I have never personally abraded any screens, but I figured that the vinyl would have a hard time holding on to begin with. I should also mention that some companies that I can't recall the names of have old videos that must have been made in the eighties that have been uploaded to youtube where they use products they sold to abrade new mesh.

No degreaser?

I am pretty sure I saw the article you are talking about in the articles on Kiwo's site.

Yep, Ulano still stubbornly holds on this process and sells more than one product. The fact that they even mention not to use it on silk tells one that this is almost forty year old thinking. (Interestingly, I see that they mention the nylon mesh, so I am remembering this era correctly) I have no idea if nylon is still common for flat stock.

btw, you do understand that I wasn't trying to be overly critical, but didn't want obsolete, possibly harmful info going out to newbies if possible.

Now, if anyone has had problems adhering stencils because they didn't abraid, , let me know. We can discuss the pros and cons of using of abraders in the screen making section, hopefully with some industry experts.

[DouglasGrigar]

The effects of household abrasive cleaners on mesh shown in the above photographs.



Even the made-for products with smaller abrasive particles cause the damage seen here (above), this is considered proper use of abrasives for cap film use. There continues to be debate about the use of abrasives, one point in favor of its use is the fact that cap films do benefit from the roughened mesh in holding and longevity of stencil use, and even a more secure application. Gain something lose something proposition.

The problems with abrasives are obvious, mesh damage, more difficult cleaning and reclaiming, changing the ink flow properties...

[Frog]

.

[StuJohnston]

Ok, I will cop to giving some bad advice. I have never personally abraded any screens, but I figured that the vinyl would have a hard time holding on to begin with. I should also mention that some companies that I can't recall the names of have old videos that must have been made in the eighties that have been uploaded to youtube where they use products they sold to abrade new mesh.

No degreaser?

I am pretty sure I saw the article you are talking about in the articles on Kiwo's site.

btw, you do understand that I wasn't trying to be overly critical, but didn't want obsolete, possibly harmful info going out to newbies if possible.

Now, if anyone has had problems adhering stencils because they didn't abraid, , let me know. We can discuss the pros and cons of using of abraders in the screen making section, hopefully with some industry experts.

No problem. As I mentioned, I am not an abrader and have only had a few issues that I have since corrected. Perhaps it was misguided, but I was thinking that even the really permanent adhesive on the vinyl that I print on, will take off paint, but I can't imagine that it would take hold of mesh wet with ink very well. Speaking of, I should search for info on cap film. There must be something to it if people are willing to pay that much for a stencil!

Gilligan, it seems sort of odd that they didn't have the right length of scoop coater, Midwest sells it by the inch and cuts it off a length of extruded aluminum, then slaps two caps on the end. You might try to get the email of their salesperson and start a conversation with them so that you will know what to ask for when/if you make the trip. As for the photo method shopping list, it's basically: scoop coater, emulsion, emulsion remover and maybe degreaser. It seems that Frog may disagree with that bit. It may because I am using solvent inks, but the last time I didn't degrease, I got not just pinholes, but certified fisheyes.

Frog, that tanks image made me laugh even before I figured out what it was for! Also, I am buying my mesh from Midwest so it's plain sefar.

[Frog]

As for the photo method shopping list, it's basically: scoop coater, emulsion, emulsion remover and maybe degreaser. It seems that Frog may disagree with that bit. It may because I am using solvent inks, but the last time I didn't degrease, I got not just pinholes, but certified fisheyes.

We have a little misunderstanding here. I never said not to degrease, I said not to abrade. Although there is a combination product available, that's not the same thing.

[StuJohnston]

Thanks for clearing that up! I didn't know there was a combo product. Something that Roger Jennings has mentioned several times is that manufacturers do not know what it's like to actually print. I don't think that is always true, but as long as there are expensive fluoro units for sale, there will be some truth to it.

To add to the evidence, I saw a video that showed a guy using soft scrub to 'prepare' a new screen. He went through three or more cycles of soft scrub, then the screen popped when it was drying! The reason he posted the video was to ask why this happened!

[Gilligan]

I have all the other products... they just didn't have the scoop when I placed my initial order.

They come through every Tuesday and Thursday so I'll probably just get that and a little ink.  Now I need two different length coaters anyway so that's another thing.

[Frog]

  Now I need two different length coaters anyway so that's another thing.

Unless some of your screens are seriously oversized, or perhaps smaller like a specialized leg screen, a coater that covers your standard width could be sufficient.
I also use a less expensive block-out (a product like emulsion with no photo reaction) and/or tape on screens that my coater doesn't cover completely.

[Gilligan]

Yeah, I guess it's less tape than I initially thought.

I do plan on "permanent" blockout (screen glue?) as has been discussed else where on this forum.  So it would be a moot point as soon as I do that.