Base white 2 stroked (pressure settings)

[Dottonedan]

Quick reply.


No argument.  . Happy guy here.


Yes, it's true, you can hold more (when comparing similar mesh counts like a 230). But what drove me to testing it was the comments that were mad e of using 55-65lpi on a 225S.   STILL, you cannot hold a full tonal range of 3-97% AND, more important to me, is to get optimum blending capability. It's similar to printing sim process or 4 clr process on a 156 mesh. You just wouldn't want to.

[JBLUE]

Ell Dan your 3% dots are probably more like 10% in reality if your not linearized and those should hold fine at 50 LPI on a 225-S. Long swaths of low percentage areas may give you some issues depending on angle. Depending on the transitions we can get a lot of 55 lpi to work as well.

[Dottonedan]

The first time of testing these 225-S and other mesh sizes, I was at another shop, with a perfectly linearized Film output using a densitometor. Then, we measured and linearized their the I-Image STEll to match the FILM.  I can't say really where that was, without permission.

I later went to work for a small screen print shop and used film there. I linerized the films there and used Accurip to adjust. I didn't really like that rip, or more so that film printer along with that rip, but it worked for what we did. I'm sure to, the 3's were not 10% there, nor were they at the first shop were we tested and I'm sure they are not 10% where I am at now. Positive. No pun intended.
If my 3's were rally 10% at any shop, then I'd be holding more of my gradation in the 225-S wouldn't I.

Still tho, 3's to 10 aside. Too much ink for my preference is all.

[ABuffington]

Just some measurements and thoughts on all of this:

1. 225/S = 42% open area and 73 micron openings.  Mesh thickness: 59 microns - Ink Volume: 25cm3/m2 - Tension Range: 18-29
    270/34 = 41% open area and 60 micron openings. Mesh Thickness: 41 microns - Ink Volume: 21cm3/m2 - Tension: 17-29
For highly viscous inks like white base plate ink the mesh opening is also a part of the mix of things to look at.  Less pressure needed with larger mesh openings, but as thread diameter and mesh thickness grow so does pressure.  135/S, 150/S, 160/S, 180/S, 225/S are all a family of base plate meshes, or high end water base/discharge meshes.  I have just found more opacity with a bit more ink volume and a mesh thickness in the 225/40 range vs 270/34. But the 270/34 is an equally good choice just more modifications of ink may be needed. It does have more mesh openings and threads for halftones to form.  Toss up in my mind, but opacity should be better on 225/40 with careful squeegee settings.

To answer the question on pressure here is my set up technique for 225/S/40.
Set air pressure to 40 lbs 
Triple duro 65 or 75 (depends on design for me, every design requires different choices.)
Increase angle from: 0 degrees to 10-15 degrees. (Crucial to obtain bright opacity with sim process printing.)
Slow down squeegee stroke in the beginning to 1/3 of desired speed. (We are icing a cake with the base plate and not trying to drive the ink to the back of the shirt that typically occurs with a 0 degree setting and scraping the ink at too high a squeegee pressure.)
Back off mechanical pressure until the ink doesn't print.
Add mechanical pressure slowly until image starts to clear. (The squeegee should barely bend, keep squeegee sharp with a straight edge for absolute minimal pressure.)
Then as inks warm up on test shirts, speed up squeegee speed gradually. At 160-190 degree pallet temp you will achieve as fast a squeegee speed that is possible without changing the set up or ink adjustments. (A turnabout ink mixer with white base ink helps keep white ink sheared to keep ink soft when added to screen.  Really helps in the winter time.)
Once mesh clears with the least mechanical pressure possible and the inks are warmed up and shearing well,  back off air pressure slightly to reduce pressure as much as possible.  This helps opacity as well as the negative dot between the printed halftones and is often the key element that makes the tonal values have as much tonal range as possible and smooth transitions.
All pallets need to be leveled to each other well to obtain absolute minimum pressure needed as described here.
Slight adjustments to ink viscosity help, but typically not needed for 225/40.  Less adjustments to ink = best opacity it can yield.

If I am holding the space between the 70-85+% dots of well linearized film with a pre press curve to compensate for 10-15% ink dot gain, then all other percentages will print fine. It's these tiny negative dots that are the hardest to print well.  Easy to hammer down squeegee pressure, but the balance point of opacity and great halftone reproduction requires modifications to angle, pressure, air pressure, and mesh choice.

2. Next is image setter:  Ink jet is all over the map in terms of making good halftones.  An older unit with a lot of mileage on it doesn't focus it's pico liter dots well.  So at low dot% it varies tremendously from shop to shop.  Some are scattered pico liter dots that never form a discrete dot.  Even well focused pico liter dots are no where near what an image setter or true film can produce, nor as opaque as wax.  So quality halftone reproduction on screen varies from shop to shop, even if linearized, depending on the quality of the dot.  Even low % perfectly formed dots below 4-6% are tinier than the thread diameter, so the dot may image but be blocked by thread diameter.

3. Then what shirt brand/ Open end? Ring Spun? singles count?  Fine weaves can handle far finer dots than a coarse open end 4.8oz fabric 

Every job is different, what I would spec on one job with fine shirts with sim process would be far different than a job on an open end with solids and halftones within the same color.  This is a subjective business where if you and your client like what you see and it sells, great, job accomplished.  But for high end printing the small tweaks we give to mesh, squeegee and inks can make a difference with many different paths to get to the 'best' result. Once you dial in your #1 head for the baseplate leave the squeegee in, and on new jobs slow down the squeegee speed only and increase speed as the inks shear and warm up.     

Al

[Colin]

Quick question Al:

Do you see many shops running their presses and getting board temps in the 160-190 range?

Here, we put the breaks on board temp around 150 - we HATE 160 or higher - so many issues crop up.... 

[ABuffington]

Hello Colin
All depends on ink type, ink print area, amount of ink to be flashed.  Just numbers from my head long ago.  Lots of low temp polyester inks out there that would favor much lower pallet temps.  The number of flashes is another issue and it gets to the point that pallet temp and ink flashing needs may push pallet temps higher with 3 flashes and not enough cool down stations. Once we hit good prints and flash times it was a juggling act of temp, time, and whether we got enough of a gel.  Add fans here, slow down a squeegee to cool down large plastisol base plates, and so on.  It amazes me we aren't all crazy with the magic acts we perform on press by making slight adjustments to keep the job running and explains why repeating a difficult job is harder the second time around. Jobs we did in winter with excellent pallet temps and 3 flashes become a nightmare in 100 degree temps with no ability to keep them cool enough.  This is one reason I like S meshes and even the 270/34 since you put down less ink, flash faster, and have that precious 1 second extra cool time when trying to run as fast as possible.

[Dottonedan]

Here's the thing about wet ink DTS printers that people always overlook.  If the dot is linerized before screen, and total dot gain is controlled after, (on screen to on shirt), then there is no debate.  In this case, a 5% is a 5% (there abouts).  So the whole "Wet ink doesn't form a good dot statement (made by anyone), not just Al, doesn't hold up.  Now, I will concede and agree, that everyone who has wax, getting great hassle free dots, is doing great. They love those machines...and why wouldn't they?  They bought (invested in their decision). Same for the I-Image users. That wax is working for you. It's hassle free (so you think), as it looks great on the surface. Is it correct? Is it really great?   I know it's not (from the standpoint of a dot snob). Now, neither is a wet ink device.
The wet ink DTS  I am most familiar with is the I-Image. I started out at two different shops at the forefront of WAX dts in two different shops. I'm familiar with wax output, but in recent machines. I've studied wax dots/shapes density in today's machines but not in great detail about the guts of the wax machines so I am a novice in that area compared to WAX dts experts.

The standard print setup of an I-Image has been tested and proved to provide a Dmax 3.6-3.9 based off of multiple shop setups readings from a transmission densitemeter.  Since Dmax represents the area of the darkest opacity, and should be as high as possible or, above 3.0 I can safely say, this ink in the I-Image, with the settings of a typical installed 12 passes at 900 x 1200 ink output resolution at 8 picoliter, using bi directional printing provides higher than the minimum.   I have not read the Dmax of WAX but I'm sure it's solid. Both of these 3.8 and solid will provide enough density to reproduce a dot shape (whatever the shape) accurately with no visual difference.
The old idea of (must have a hard, clean, round, vector like circle or oval shaped dot) bares little to no fruit when you know and adjust for gain. That's the key tho isn't it? You need to know where you are.  You can expose the right tone percentage using a crusty 24 day old dried booger. As long as that size represents yours targeted %, you can expose all of the boogers you want.

Wax is opaque, I give you that. No argument.  Having said that, know this. The idea, that WET INK is not, is not and accurate statement.
This is why WAX dots (on the surface) or in general, look good. The wax forms non uniform blobs of wax drops. (It works for screen printing) and that's what matters. It's rounder...and easier to hold as a result of it's lacking the ability to reproduce exactly in a minute manor. A wet ink dts can form the 1% (pixel cross). That's how accurately it reproduced a bitmap image. How do I know?  Been there, done it.

 So I know, we cannot print a 1% dot in a 65lpi on a 300 mesh...or insert S mesh. Bare with me for a moment here, I'm not referring to holding.  I'm referring to SHAPE.  There is a common statement that WAX is better and I'm here to say, WAX is great...and so is WET. I am not a believer that WAX is "better".  Just different.

I used to ONLY believe in high end film image-setters but I've been convinced that it's not the shape that counts, it's the tone that is represented. Think about it.  Sim and 4 color process can be printed with pixel squares (stochastic dots), Not even perfect squares. Many are more like (individual pixels hanging out on the outskirts of a a fade to 0%. We can print with mezzo tints, line patterns, etc. You pic a shape and you can print with it. So the fact that WAX can only put down little blobs is of no concern. It works.
Some low end RIP devises and auto sep programs are using 300 ppi bitmap halftone dots every day and the customers love the prints (regardless of how much we feel they are inferior). Some people prefer not to buy a RIP at all and will do theirs manually in Photoshop. I recommend 600ppi myself.


So how do I know that the true shape of a WAX device is not reproducing the same cross as a 1% (in a very high lpi)? Because I have had a few files (The tif files) from ripped images.  They are simply a 600dpi tif image. The Wax devise used this to image onto the screen...but it does not reproduce it idential (or close to) identical as what is in the tif image. It can't. The wax itself is too thick in consistency (for the lack of a better word).  Here is a WAX devise tif filed used to image onto the screen.WAX_DTS_halftone dots_720dpi_rez output...600 dpi printer_BitmapTIF_55-60lpi_small


So the WAX .tif file used is the same quality as the WET INK PRT file.  The lpi dots are made up of 600dpi pixel dots in both. Both look chunky. The WAX device puts that shape down (less chunky) since it's wax consistency can't duplicate the smaller shapes exactly as in the file. THIS, is the "visual benefit" to the screen printer, but that's all it really is. An optical lie. It's not "better" or more superior. It's actually the opposite that is making the WAX owner think it's better. Does this matter?  No.  It's working. Good is good. Easy is easy.

The WET INK is more of an accurate reproduction of the 600dpi printer. Therefore, "looks less clean or less rounded and more "600 dpi pixel like.

If I'm wrong, I don't mind someone clarifying. This is what I've found to be true, but I can be mistaken and I'd rather learn that I'm wrong and find new or more accurate answers. Lastly, All of this detail, (the explanation), doesn't really matter. Doesn't matter if it's WAX or INK. They can both do award winning prints in the right hands.

[DannyGruninger]

Dan, here's a question to you........


Does emulsion surface tension and RZ value effect the way the wet ink lays on screen?


From my testing emulsion surface tension has more to do with quality dots on mesh then almost anything else....... And from what I have seen surface tension and rz have little to no effect on wax dts but I dont know how many shops I've been in that switch emulsion and all of a sudden their ink jet dts cannot print worth a damn.


lets hear your thoughts on that as in my shop huge difference between wet ink and wax specifically because emulsion surface tension

[T Shirt Farmer]

Dan, here's a question to you........


Does emulsion surface tension and RZ value effect the way the wet ink lays on screen?


From my testing emulsion surface tension has more to do with quality dots on mesh then almost anything else....... And from what I have seen surface tension and rz have little to no effect on wax dts but I dont know how many shops I've been in that switch emulsion and all of a sudden their ink jet dts cannot print worth a damn.


lets hear your thoughts on that as in my shop huge difference between wet ink and wax specifically because emulsion surface tension

Danny
Is emulsion surface tension measured in newtons like mesh or duromatur like blades?

[Colin]

What he is referencing - as I understand - is the receptive nature of all emulsions to being directly printed on.

Some emulsions the ink will wick like crazy going all over the place - others the ink will stay right where it dropped - think water proof Vs. non waterproof etc.. inkjet film.

Within the wet ink direct to screen machines/families - the different inks used all have different results when hitting the screen.  I personally saw more "dot gain" when we switched to t6 then with D2a.  I needed to recalibrate my machine.  The actual difference was up to 4%.

[Dottonedan]

Good question from Danny  and I would say that Colin is correct.

What Danny mentioned, (RZ value), Is about the only KEY question where WET INK loses in comparison.
WAX ink, is not as sensitive to extreme or poor environment differences and processes. In other words, With WAX, you can relax your grip on process control more and allow your shops environment to be less than adequate. THIS, is good news to some people and more appealing to go wax.

For example,
RZ VALUE
* Your coating technique can be  (too thin) causing the screen "mesh" to be more obvious with a vacuum like form fitting skin after it dries. That's too thin for good stencils in most peoples book, yet it's very common. People want to get away with the least effort in their screens. This will interfere with your stencil durability and quality, but you coat faster, dry faster and expose faster, but people like it.  To point out that a good emulsion surface (good RZ value), a smooth surface was still desired back when using FILM POSITIVES. This smooth surface helps forma  good gasket between the stencil surface and the substrate (garment) during production. This forms good side wall and image detail. Lower RZ (rougher surface where you see mesh thread shapes) are prone to permit ink being pushed out for the sides leaving some smearing or bleeding from one color into another.

Heat as I understand it is not normally an issue with WAX nor WET INK. Not too many people hit a re-melt stage in their environment. That has always made me wonder about people who expose on a metal halide with long exposure times on really low mesh, but I've never heard of it re-melting.


Since WAX is not affected by RZ value (as much), it wins in that category. Your screens surface can be of a lesser quality and that does not have an negative impact on dot imaging. To elaborate further and provide an extreme scenario as an example, It would be affected by the hills and valley's of mesh thread if in this extreme example, you can visualize a really low mesh like an 80 mesh where the dots (if you were to use dots on an 80 mesh) are not able to lay flat ...since there is no real flat surface on an 80 mesh with a fast coating of a 1:1 coat. The WAX dots would lay more at an angle as they land on and are formed on the side of an emulsion thread. That's about the only way were RZ value has an impact with wax.In this same scenario, WET INK would also from on the side.  In general or in 95% of all cases where I had done installs or had came to a shop to provide assistance and trouble shoot in over 300 shops, any issues with the imaging onto screen, exposure, or dots on the surface were due to poor processes. Rarely if ever (in my experiences) was there an actual issue with someones emulsion. If there were, we would look at changing other ares to accommodate that emulsion. Having said that much on emulsion, there (were) some or one that just didn't do as well with the LED exposures). That's another story. In fact, I don't recall ever suggesting to a customer that they cannot use their current emulsion myself, but I know when we do trouble shoot on the phones, that's one of the questions we ask, (what emulsion are you using), but that's more to understand the characteristics of that emulsion.

HUMIDITY
Another extreme scenario would apply with low humidity...where the air is too dry. People can work in a very dry humidity and never notice any affect (on themselves) that it's too dry. They just work though it and use lotion. With some older I-Image inks (K ink), was very sensitive to low humidity. It would leave a dull surface in solid black areas of say "bold type" and would even crack like a dry desert.  If not exposed right way, you would see this in your washout. Again tho, this is in extreme scenarios. K ink was used widely with no ill affects while in some environments, they would not use it. They may have tried other emulsions that might have helped them in those cases, but in general it's not your emulsion but your environment.

HIGH HUMIDITY can be a problem as well. Since the ink is WET, if your emulsion stencil is still damp, (not dried well),or your humidity is way up, you can have your wet ink sort of (soak into) your soft stencil and fatten/spread and worse, become less defined. Again, tho, this negative that is found when using wet ink...is due to an extreme scenario in your environment...and not the ink. If you have these problems, the WAX will not be a problem and the issue (while still an issue), would go unnoticed as it pertains to imaging the screen. you will just have other issues further down the road with soft stencils during washout.

EMULSION TYPE
Like mentioned, I'm not aware of any specific emulsion that I could not get good results from using a WET INK. emulsion TYPE is not typically an issue or "your" issue. I would lean in other directions for finding answers to any specific issue. Changing to get better results would not be my suggestion (as it pertains to imaging onto screen and wash out). Some have different characteristics but can be worked with. For example, While out in the field, there was one emulsion that had a certain feel to it. I can only describe it as a velvet rubber. It was very sooth and provides a great surface. I believe it is in the Chromaline family. I didn't like the feel of it...but it worked VERY well. In fact, we use it now in our shop and we get great results. We print as high as 85 lpi in actual production and typically at 65lpi and burn plastisol and discharge screens coated 2:1 with an auto coater.


The answer is CORRECT, WAX due to it being WAX, is not affected by environment in the way that WET INK is. Know this tho, None of that is a negative about the WET INK. It's a negative about your specific issue in your processes or your specific environment that is affecting other areas such as the wet ink.  It's like not having a dehumidifier in your drying room and then complaining that your screens take a long time to dry so you blame the emulsion.

[ericheartsu]

Dan, this is really really really helpful information, and i'm really excited you posted about it.

I would love it, if there were more references, specifically videos on how to test and measure things like EOM and RZ. Especially for dummies like me, where I understand the concept, but never really know if i'm testing it correctly.

[Stinkhorn Press]

RZ (smooth surface) is more important with film FOR EXPOSING PURPOSES
RZ (smooth surface) is less important with wax CTS FOR EXPOSING PURPOSES except in extreme scenarios
RZ (smooth surface) is of middling importance with wet ink CTS FOR EXPOSING PURPOSES

i can see that.
but in my shop, the PURPOSE of a decent RZ is how it PRINTS not how it plays nice or not with various art on screen methods. RZ helps with exposing film, less helpful to expose wax dot. OK. But 90% of the function of RZ is printing not exposing.

am i missing something there?

[Doug S]

I know I'll sound like an idiot but I must of missed it what is "RZ"? 

[Dottonedan]

RZ (smooth surface) is more important with film FOR EXPOSING PURPOSES
RZ (smooth surface) is less important with wax CTS FOR EXPOSING PURPOSES except in extreme scenarios
RZ (smooth surface) is of middling importance with wet ink CTS FOR EXPOSING PURPOSES

i can see that.
but in my shop, the PURPOSE of a decent RZ is how it PRINTS not how it plays nice or not with various art on screen methods. RZ helps with exposing film, less helpful to expose wax dot. OK. But 90% of the function of RZ is printing not exposing.

am i missing something there?

YOU ARE CORRECT.
Years ago, before it was semi-common to have DTS, the only reason we desired a smooth surface was for two reasons that I am aware of. Yes, in film. Most had light sources with light scatter, so the better the stencil surface, the better the contact. Thats why vacuum is important as well. This results in less scatter affect. 2ndly, is in production for contact to garment or in production to improve imaging to substrate/garment via a better gasket/seal from stencil to garment surface.


Now that we have these discussions about WAX or INK for example, it's possible for these examples/comparisons to get pushed towards favor of one or the other. In many cases in my opinion, some facts only apply in exaggerated or worse case scenarios. Similar to how one might say (This emulsion is no good because you can't run 100,000 prints on it without it breaking down). Ok, in reality, the typical shop can stop and load in another set of screens if it only last for 50,000 prints.  Sure, it's "better", more profitable if you don't stop production, but most shops don't get these orders every day and the common emulsion they normally use might be jsut as good but perhaps you may stop and load new screens. It's a give and take or a decision as you get into many of these examples. It's common and not too costly to burn two sets of screens (just in case) on a 100,0000 piece order. A manufacturers may give you a worse case scenario fact as an example for every day production. It's selling point.