# Alternative to white underbase- A discussion



## markc (Jun 3, 2009)

Pastel Lites 
I have spoken to number of people in the industry over the last two years about this and specifically refrained from talking to some others, for some obvious reasons.
I now think it is time to bring the topic forward for a more general discussion. At this stage of the industries development working away in secret just means someone else will beat you to the punch.

About two years ago we (arakis inkjet) stopped doing "white underbase" for two reasons, the usual clogging of the heads because we used Epson4800 head and the available white inks didn’t hold the titanium in suspension.. 
The problem as we all know is that the if the ink gave a good print it was too thick for the heads and dampers ( it has got a lot better since then)

This made us analyse why we wanted to do it, the answer was everyone else was. This is not the right reason to do something.
Screen printers use opaque inks, not transparent. If you want yellow why put down white put down opaque yellow, Red opaque Red etc.

We then went and made opaque ink, basically about 20-30% color ink added to white gave an opaque color ink that worked under single pass on dark shirts.
A second coat of opaque or transparent on top would boost it.
Because we were not putting down a thick white the flexibilty was better, there was a bit of problem with bleeding, fine tuning the ink / pretreatment cured that.
Drying between coats also helped.
Washability was better as the colour was mixed with the white and not sitting on top of it.

Printing white on this system means you now need another set of heads, as you need, standard Colors for light shirts, Opaque colors for special effects and darks. And white for white.

On one of Belquette’s or Texmac duo double headed units it is easy , there are probably some others that can do this as well.
You need at least 10 or 12 sets of inkjets, to do this properly, and they should be able to handle larger drop sizes or else you have to run thinner ink and more passes.

We have now been experimenting with two new modes of creating the opaque inks, both of them are machine based and mean we only need to have CMYK and W tanks, the first is the simplest and possible the best ( further testing) mixing on the fly, we print single passes of W and Color, where the head is aligned W,C,W,M,W,Y,W,K and the ink is deposited on the same firing pulse and mixes in flight/on shirt.
Currently this works better in multipass mode. Benefit could work for 8 nozzle system, but a bit slower.

The other way is to have mixing valves and blend the inks on the way to the head, this could be computer controlled for special jobs etc and also enable Spot colors to be added later, Benefit much faster and colors more stable but need 12 nozzle sets
Once you get up to that number of heads ( nozzle sets ) putting down pretreatment is also a possibilty, you just have to work out a few procedural and mechanical fluid vapour things and it is very practical.

Profiling and rips have to be tuned up, but that is just a once off, and since in The US most rips come from Fred, I know he could sort this out pretty quickly.

Arakis Inkjet - Digital Garment Printer Engineers


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## Titchimp (Nov 30, 2006)

Hi Mark, 

Thanks for sharing what you guys are doing. I think most customers/potential customers would agree that the industry needs more transparency but i guess in some ways it might give some companys a free ride  

I take it the epson heads are not going to work with this ink or would they? I like the look of your printers, are they on the market?


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## markc (Jun 3, 2009)

Hi Nick

Yes it will work with the Epson heads, it comes down to how the machine is built because the ideal is to have multiple heads


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## YoDan (May 4, 2007)

*"Good information from another tester"*
Nice to hear that there are other attempted options and testing going on, keep it up and give Jay a kick in the back side for me 
Dan
*"HAPPY PRINTING"*


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## zoom_monster (Sep 20, 2006)

Mark, I hear what you are saying. Currently the Anajet RIP does have a mode that alows printing the White and CMYK at the same time, but since in reality you need such a high high ratio of TO to pigment it give a cool effect but nothing that I could call accurate. Perhaps some kind of multi pass algorithm with an extremely accurate pattern might be able to create a believable image.


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## markc (Jun 3, 2009)

zoom_monster said:


> Perhaps some kind of multi pass algorithm with an extremely accurate pattern might be able to create a believable image.


Hi Ian 
In that mode of firing white and color jets together we have just used it to get a pastel effect on block colors or for underbase for high definition color on top.
We have developed a multipass mode that lets us put down a few coats of pastel or color before the head or platten steps.

Having a complete set of mixed pastels is better, if you have enough heads available, this lets you print a high definition image in pastel.Its like using standard epson Light colors on photo paper


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## zoom_monster (Sep 20, 2006)

markc said:


> ......
> In that mode of firing white and color jets together we have just used it to get a pastel effect on block colors or for underbase for high definition color on top.
> We have developed a multipass mode that lets us put down a few coats of pastel or color before the head or platten steps.


This is similar to the way our driver(along with the RIP) can be configured. Multiple inline passes before the table indexes.




markc said:


> Having a complete set of mixed pastels is better, if you have enough heads available, this lets you print a high definition image in pastel.Its like using standard epson Light colors on photo paper


 So the pre mixed pastels... do not those tend to settle out also, or are they more stable? Are we talking Epson heads?

Also Mark, When using Opaque CMYK, does that not throw off the effect of mixing those colors? I know some people are experimenting with Hex sets and possible spot colors, but you open a whole new can of worms there...


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## markc (Jun 3, 2009)

Hi Ian 
<So the pre mixed pastels... do not those tend to settle out also, or are they more stable? Are we talking Epson heads? >

Yes we test for Epson 4800 heads( which are the worst) The white ink settles out, but not quite as much ,the ink is a bit thinner then normal white with more suspension agent from the color ink. Result less clogging

< does that not throw off the effect of mixing those colors? > 
When mixing these colors you can't have high levels, your max ink density has to be kept low so that you are getting visual mixing without the inks touching ( too much).
It is similar to doing process screen printing with stochastic dots. We worked on that about 10 years back and got pretty good results. 
You have to profile though, can't guess what the colors will be.
Hex, Can see the benefit but have enough problems with CMYK for now.


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## vctradingcubao (Nov 15, 2006)

Hi Marck! Are you still planning to use Valve Jets for the white underbase? How different is this setup from Inkjets?


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## zoom_monster (Sep 20, 2006)

Mark, I can appriciate your knowlege of stocastic printing, and the importance of keeping ink level as low as possible. I've seen some impressive work myself. My vision with this, would be to kind of have a hybrid where the CMYK+(in your case pastel) would be tweaked so that they would create a limited but very accurate stocastic pattern. The fine work I've seen on t-shirts consisted of 200dpi square dot and 8 to 12 spot semi-opaque colors. So let me understand, are you proposing using the pastel as an underbase and boosting the color with the CMYK?


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## markc (Jun 3, 2009)

vctradingcubao said:


> Hi Marck! Are you still planning to use Valve Jets for the white underbase? How different is this setup from Inkjets?


Hi Byron
We are still playing with the valve jets, but couldn't get the ink thick enough with the ones we were using so back to drawing board on that.
Currently we are doing the pastels with high volume inkjet heads, and very accurate pretreatment.


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## markc (Jun 3, 2009)

Hi Ian
I have also sent you a PM.
We used 200 ls and also a square stochastic, for silk screen 
We can dial in 1x1 2x2 or 4x4 dot elements so we can vary it for resolution. So when we go full digital instead of actual screening we run a 2x2 for the underbase at 720, this gives us large dots as if we were running 360 underbase and then we can put the CMYK down at 720 1x1 for fine deatil and color control.


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## vctradingcubao (Nov 15, 2006)

markc said:


> Hi Byron
> We are still playing with the valve jets, but couldn't get the ink thick enough with the ones we were using so back to drawing board on that.
> Currently we are doing the pastels with high volume inkjet heads, and very accurate pretreatment.


Yes, the valve jets seems like a good idea also. I exchanged some correspondences with Jay on the possibility on the posssibility of visiting your factory when you get the new machine going. Hopefully, I'll hear from you guys again when it's ready.


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## zoom_monster (Sep 20, 2006)

Sorry a little off topic......Any chance of using Valve-jet heads for pretreatment? In looking at your rotary design, you could have it more isolated from the piezo. Of course, it would have to be made to work wet.


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## vctradingcubao (Nov 15, 2006)

Is that a valve jet Kornit is using for their pre treatment?


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## zoom_monster (Sep 20, 2006)

vctradingcubao said:


> Is that a valve jet Kornit is using for their pre treatment?


 I don't know....certainly don't want to copy anything that Kornit does


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## markc (Jun 3, 2009)

zoom_monster said:


> I don't know....certainly don't want to copy anything that Kornit does


No they are using a spray nozzle system
Valve jets work very well for the pretreatment, Some inkjet heads also work very well for this. Depends on which pretreatment you use.
I don't know why but Kornit really saturate their shirts and print wet, the dupont style inks don't need so much fluid so inkjet heads can do the job.
I am surprised that DTG USA aren't using the DTG Europe pretreater, seems like one of their better ideas.

Anyway back on topic for Byron
The valve jet head we were testing had nozzles no larger then some of the inkjet heads, and the pressure needed to spray the ink was so great it caused the ink to spider web. 
We have now found some larger nozzle valves but have to build our own head. So with all of that we think the pastels and something else we are working on ( no hints at all on that for a while ) could be a better overall solution.


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## markc (Jun 3, 2009)

markc said:


> About two years ago we (arakis inkjet) stopped doing "white underbase" for two reasons,
> 
> We have now been experimenting with two new modes of creating the opaque inks, both of them are machine based and mean we only need to have CMYK and W tanks, the first is the simplest and possible the best ( further testing) mixing on the fly, we print single passes of W and Color, where the head is aligned W,C,W,M,W,Y,W,K and the ink is deposited on the same firing pulse and mixes in flight/on shirt.


 
Just saw DTGs posting about doing one pass underbase and colour, which I guess they are promoting since Kornit have come out with it on the Breeze.

I guess those of us who have been doing this stuff for years, have to watch out that someone is not trying to lodge patent claims against "prior art" which as we all know is once someone tells you an idea or tells you they are working on something it becomes "prior art".
Just because that person doesn't lodge a patent doesn't mean you can.

So as I have suggested before this forum should be used to protect our business from bogus patents.

Now as DTG are suggesting they have a special board to do this and they are putting a patent on that board, well that is a legitimate use.
But trying to patent using and epson or similar based tshirt printer to do single pass would not be because of discussions we had about 2 years ago around the time of the vipers inception.

As both Anajet and Belquette know from their own tests putting down both the white and colour together have some limitations. There are some jobs that come out as good or better and others that don't work so well as you can loose some definition on the details. 
Our latest printer, as described before has the ability to print multiple passes of any colour before the head steps, I understand Anajet also can do this.
So like the Kornit you do a white swath and then on the same spot you do a colour swath and the then the printer steps.

Next stage. 
On head drying, if at this point the ink behaved like UV ink and you could flash dry it without heat we would overcome bleeding issues.
This concept is being worked on by ink guys and machine builders and is not that far off, you just need to skin the ink not dry it completely, so it only takes a small reactant agent in the ink.
We have laready tested solid state IR, but they are not powerful enough so we have moved to UV, powerful but no heat.

Ideal tshirt printer 
On machine pretreatment only in the exact areas where the image is going to go.
Single pass base layers, either white or color
Flash curing on printer
Single pass colour layers of any ink depth ( multi swath).

There are probably hundreds of ways a machine like this can be built, and it will be the variations in the way they are done that will decide market acceptance and will move our industry on to the next level.


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## mrbigjack50 (Jun 9, 2008)

Issue I see with "instant dry ink" like UV inks are that they are thick/dense.
You won't get soft feel touch as you do with waterbased inks, UV inks dont really penetrate the substrate but stays on top like screen inks.

I think Hp has come up with an ink, at the moment for large format roll material using latex inks that instantly dry with pass through of heat quickly, I notice they are promoting inks for textile usage


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## vctradingcubao (Nov 15, 2006)

Sean, plastisol screenprints feels thick & dense anyway, & it has become sort of an acceptable industry standard on dark garments. A Kornit printed dark shirt also feels thick & dense and I think this is necessary if you want your white underbase to be as opaque as possible & thus get brighter colored prints. Mimaki's Discharge fluid system for dark shirts (patent pending) gives you the very soft prints, but this will not give us bright final results, as it is dependent on how well the dark shirt dye discharges. If Mimaki (or another company) could find a way to add some sort of a pigment white ink after discharging, even if it's "not very opaque", this would be similar to discharge screen printing, and could really become the holy grail of dark shirt printing.


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## mrbigjack50 (Jun 9, 2008)

I guess i am spoiled to love waterbased prints Ha.
What makes white ink so stiff? Is it titanium oxide, which I assume is some sorta mineral ie. why shaking needed for no settling.
There are over pigments beside titanium oxide to make white, I know this because i sold art supplies for 5 years and there was white ink with titanium oxide and white ink without and believe me when I say it felt light density/weight wise.

I love idea Mimaki but discharge leaves garment pink, why can't than use some sorta white ink with titanium oxide or ie soft white color, because there is softer tones of white that dont use t.o.


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## vctradingcubao (Nov 15, 2006)

mrbigjack50 said:


> ..I love idea Mimaki but discharge leaves garment pink..


I think this depends on the blank shirt used, & yes, this is where it's difficult-finding a good & consistent "discharge ready" blanks.

Mimaki's Discharge+CMYK mode could give you a very light grey shade...



mrbigjack50 said:


> ..why can't than use some sorta white ink with titanium oxide or ie soft white color, because there is softer tones of white that dont use t.o.


Maybe they are working on that already, .


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## mrbigjack50 (Jun 9, 2008)

I better patent the idea and sell it for millions haha


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## vctradingcubao (Nov 15, 2006)

mrbigjack50 said:


> I better patent the idea and sell it for millions haha


Well, you are already "well documented" here, so no one could take that away from you now,  ... save some screenshots of this thread,


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## FredP (Jul 2, 2007)

markc said:


> I guess those of us who have been doing this stuff for years, have to watch out that someone is not trying to lodge patent claims against "prior art" which as we all know is once someone tells you an idea or tells you they are working on something it becomes "prior art".
> Just because that person doesn't lodge a patent doesn't mean you can.


Mi Marc,

Good to hear from you. I remember that conversation we had. You have been experimenting with and implementing that stuff for years. I think we talked about it 2 years ago or so. Just for the record, it is not me who's trying to patent anything. As a matter of fact, while you are correct in assuming that I can "sort it out pretty quick ", it wasn't me. I have been elbows deep in the new "Adaptive FM Screening" (variable Stochastic) system for our Film RIP (PowerRIP ScreenPrint and all it's private-labled versions) which will be launched next week. As far as the uni-pass stuff goes, we will cater to whatever DTG wants to do in the U.S. As far as patents, I question wether ANY of this stuff is patentable in a way that can be protected which is why we usually don't bother. We'll see how this all plays out. Hope to see you in Long Beach next month.

-- Fred


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## markc (Jun 3, 2009)

Hi Fred

I know your position on all this, you are the software guy which is cool. Re the variable stochastic, I am glad to hear there are screen printers using it, over here most have stopped, except if they are doing CDs and small stuff. I have always thought it is fantastic on shirts, but try to get a screen printer to set it up for a 6 colour ( underbase CMYK and white ) they will throw you out of their shop. But with the right gear it means you can really pump through a lot of short run orders, don't have to mix and wash out inks.
Which is why we are working on our new project,,,,,,,,,, and we may need some slick screening.

Anyway I have question for you, do you know anyone who has made a board for the epson that only steps the paper/platen forward on every second, third or fourth step. Do this so you can do multipass on the same spot. (Like the Kornit ) . I think Mark and Brett have it in their printers.
We have one but I wanted to discuss a problem that comes up every so often. We have found that although jigging the software to stop the step forward is OK the board is faster, and since we are already taking control of the motor and the encoder pulses on the control board it actually only costs about 10 bucks to add this feature.


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## FredP (Jul 2, 2007)

Actually, I'm the "U.S." software guy ;-).

The stochastic on our film RIP is "variable" which means it can be made to simulate any "ruling" so to speak which really makes it viable for screen printing. In other words, you can have any "coarseness" of stochastic you want because it's variable. The results are awesome. Better detail, etc. I'll post some pics here after the craziness subsides a bit 

On the "skip step" as I call it... I don't know anyone employing that exact method yet but I have discussed that very concept with a couple of people. 

You could set the page size in the print file header to twice the actual length, then send the printer:

--- white raster ---
--- color raster ---
--- white raster ---
--- color raster ---
..etc..

And skip every other feed signal to the feed motor. This will cause the color rasters to land on top of the white rasters. The time savings would not be as pronounced as the channel interleaving (WCWMWYWK) approach because the print head would still need to travel in the X direction twice per band. However, the quality would be much better, and closer to the 2-pass approach since it is in fact doing 2 passes. It does save quite a bit of time, though since the tray (or printer) doesn't have to back up, re-home and perform the "ready dance" normally exacuted at the beginning of a page except at the very beginning of the print cycle. This is a major time saving for some printers that take a while to rewind and/or start the next layer. One limitation is that you of course have to RIP the color & white at the same resolution (not that big a deal). Another challange could turn out to be the microweave pattern, particularly on printers that do their own (like the 4880). I think it will work, though. I talked about this with Mark from Belquette over a few beers at one of the trade shows a while back. 

-- Fred


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## zoom_monster (Sep 20, 2006)

Mark, Not sure if it's hardware or software, but I've used the feature on the Anajet. As I mentioned before, the single pass white/CMYK works best on Natural and light grey shirts and gives a little pastel or pop to some colors. For the darkest shirts the coverage would need to target more than just the CMYK pixels(the negative area between the pixels?). I'm guessing this ratio of white to CMYK is why most people prefer to print the white layer at a 1440 step rate. Perhaps with your semi-opaque ink idea, Fred's RIP expertise we could get a doubling of dark shirt output.


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## FredP (Jul 2, 2007)

zoom_monster said:


> Mark, Not sure if it's hardware or software, but I've used the feature on the Anajet. As I mentioned before, the single pass white/CMYK works best on Natural and light grey shirts and gives a little pastel or pop to some colors. For the darkest shirts the coverage would need to target more than just the CMYK pixels(the negative area between the pixels?). I'm guessing this ratio of white to CMYK is why most people prefer to print the white layer at a 1440 step rate. Perhaps with your semi-opaque ink idea, Fred's RIP expertise we could get a doubling of dark shirt output.


Hi Zoom,

I didn't do the Anajet RIP, that's the EK... but... I can tell what is being done just by watching the printer. First, a little primer: In the direct-to-garment arena there are 2 kinds of Epson printers used: 1) The "Pro" series (4880, 7880, etc.) and 2) The "Desktop" series (1800, 2400, 1900, etc.) The Pro series does "hardware microweave" and the desktop series does "software microweave". Microweaving is (the short description) how the printer interleaves the rows of pixels to achieve a smooth print. If it simply fired all 180 nozzles and stepped 180 rasters it would leave artifacts... and it could only print at 180 dpi ;-) It is a VERY complex algorithm as the heads are actually only capable of printing at 720 dpi in the X direction so there are multiple "sides" to the pixels, etc.

On a Hardware microweave printer, the RIP simply sends the printer rasters 0 through Yt in sequential order (Yt is total rasters), that's it. The printer uses its internal processor to microweave the rasters.

On a Software microweave printer such as the Anajet, HM-1, K3, Mod1 and others (1800, 2400 and 1900 based) the RIP has to microweave the rasters before it sends them to the printer. This places an additional computational burden on the RIP but it also affords a good degree of control. You can, for example, "repeat" a band of data by sending it twice and not sending the advance command (very simplified explanation). I believe that is how they (Anajet) do the "multi-pass" color for greater density (I do it a bit different, I tighten the microweave and don't repeat). Now, if you take that multi-pass approach and send the white data to the white channels on the first pass and the color data on the second pass, you have the single-pass white/color. No hardware mod required. I'm pretty sure that's how Anajet does it. This approach would not work on a 4880-based printer without hardware mod because you can't force it to repeat the band in software (although you can do "other" things).

The white ink has come a long way but you can't escape the laws of physics. Right now there will be some bleeding if you hit the white with color that soon, that's just a fact. You have to scale back the white and play games with the color to get "decent" output. Of course, you could just promote that as "ink savings" ;-) Bottom line is that there are ways around some of the problems but as of right now, single-pass white/color cannot physically match the quality of 2-pass white/color. Never say never, though... lets see what next year brings.

-- Fred


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## markc (Jun 3, 2009)

Hi Fred,
I was just pointing out to others who didn't know you that you were the software guy, as you have admirably demonstrated in the last couple of posts. 
I know someone over here who writes his own microweave for the pro series, I will check if he knows something I don't maybe it is possible.??

Sean, I just didn't get a chance to respond to your post, we have a few people who go and do a white discharge on their shirts and then digitally print them, not perfect but is cheap in the 20 up quantities.
We have tested using bleach and then printing directly on top while it is still wet, gives great result.
But the bleach kills the print heads real fast, so we are looking at two part bleach which activates on the shirt. Our first attempt caused an explosion, stuff is similar to rocket fuel.

Mark


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## TahoeTomahawk (Apr 12, 2006)

Hi Marc,
The idea sounds great, but I have a few questions.
Sorry if they have already been asked, I didn't have time to read all the responses.

1. Won't blending the white ink with colors also introduce similar clogging problems as printing with the raw white?

2. Won't the blended ink need pretreatment, not to keep it from being absorbed into the fabric but to help it bond with the fabric. Todays white ink will wash out with no pre-treat, but colors seem to bond perfectly.

Thanks


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## markc (Jun 3, 2009)

Hi Adam

Yes blended ink has nearly all the same problems, and yes it does need pretreatment.

We did find that with the blended ink you do lower the average concentartion of white particles and increase the amount of binder, and just this 10% variation reduces the problems enough to cause less headaches.

Using different printheads is really about the only way to beat the white.

Pretreat, like some guys in England we are putting pretreat out via printheads, which built into the same machine as the white and colour gets rid of that problem, but we have to make sure we don't introduce more. Thats the part that takes up most time.


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## TahoeTomahawk (Apr 12, 2006)

10% is a great reduction. Are there more binders in the CMYK inks that in white?

I don't like the idea of putting the pre-treat down with the print head because you still need to use something sticky to press the fibers flat to get a nice crisp print. It's almost as easy to continue to pre-treat the way we do today IMO.

I don't think filibration is only a problem for DTG, I see some pretty terrible screen prints that could have come out excellent if the fibers were pressed before printing.


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