Example of halftone readings from an non linearized RIP

[abchung]

For those using Accurip..

the ability to adjust your tonal curve was removed in the last update.. when asked, they said you don't need it.

this just proves how wrong they are.

Well, that's just not right. Thanks, I'll have to remember to not upgrade...

Steve

Thanks for the info.
When I get print error, I have to turn off the Dot Gain Control in setup. After printing a job, I turn it back on.

I think they just don't want to admit they could not fix a bug in the software.

[Dottonedan]

Abuffington- thanks for that, I had the same thoughts on halftone shape/angle.  I like nerding out on this even though you're correct that the finished print viewed at normal distance is the real test, not so much the technical details we tend to focus on.   Let us know what you find on your Starlight resolution v. MH testing!  We still have our MH still setup to test this but haven't been able to for lack of time.  For textiles up to 60lpi the Starlight has easily been "good enough" for us.

We often refer back to the idea that there is a standard or "typical" viewing distance to judge a print) and that usually falls back to a purchasing decision distance or (in a store) when you walk by and say, that looks good. This is said to be the 3 seconds at 3' rule.  These numbers change, depending on who you talk to. Some call it the 5 second and 5' rule and 5 seconds at 7' LOL.

What I think is more important is to mention the print approval distance is different than the store  purchase distance. A print savvy customer will view the shirt much closer, (12" to 24" away) when they pic it up and judge your print. So print detail (for you) is more important than the varying store purchasing distance.

[ZooCity]

Abuffington- thanks for that, I had the same thoughts on halftone shape/angle.  I like nerding out on this even though you're correct that the finished print viewed at normal distance is the real test, not so much the technical details we tend to focus on.   Let us know what you find on your Starlight resolution v. MH testing!  We still have our MH still setup to test this but haven't been able to for lack of time.  For textiles up to 60lpi the Starlight has easily been "good enough" for us.

We often refer back to the idea that there is a standard or "typical" viewing distance to judge a print) and that usually falls back to a purchasing decision distance or (in a store) when you walk by and say, that looks good. This is said to be the 3 seconds at 3' rule.  These numbers change, depending on who you talk to. Some call it the 5 second and 5' rule and 5 seconds at 7' LOL.

What I think is more important is to mention the print approval distance is different than the store  purchase distance. A print savvy customer will view the shirt much closer, (12" to 24" away) when they pic it up and judge your print. So print detail (for you) is more important than the varying store purchasing distance.

An excellent point.  It's really about the end user.  We print primarily for retail sales with much of it online but a good chunk going onto racks in brick and mortar stores and each market has it's own requirements for sure. 

[ZooCity]

I also forgot to say thanks to Pierre for this post.   I'm saving those numbers in a doc for a very loose example/reference to use when training others here on pre press of where their output on the film will be compared to the PS channels when using a non-linearized inkjet to film. 

Sadly, we don't linearize with AR as it resulted in data loss and simply didn't work for us and instead will adjust values in seps to accommodate.  I know where we're at with gain pretty well but it's all stored "up top".  It works for us but when you take the head containing that information out of pre-press it's not going to work anymore and we of course will be investing in a better RIP very soon.  Saying this because I know we aren't the only ones out there who work this way and still produce good, consistent prints.

This one is much more variable but a general gain example onto a printed garment, both coe cotton and ringspun would be verrrrry interesting to have as a loose reference but not sure how you can obtain that data.   

[Dottonedan]

The bottom example is why I will suggest using the method of dividing your mesh by 5 to give you the line screen halftone you should be near (to hold the most amount) of the smallest detail halftones. (e.g 305 mesh divided by 5 = 60 lpi MAXIMUM rounded). If you were to use the 4 or 4.5 that most people use, it gives you an even higher lpi, making it all that much harder to get the smaller dots. 305 divided by 4 = 76.25 (rounded) = 75 lpi. To me, on a tee shirt, a 60 lpi versus a 75 lpi is not that big of a visual benefit, but I can hold all of my information printed onto the tee at 60lpi much easier.

To add to that, I make it even easier and prefer 50 on 305 and sometimes just 45lpi.  People say, well, I don't want to try and hold the 1% dots anyhow...but I say, you can get closer. For most of us, we can't hold the 5% let alone the 1% so your position is, Blah!  Never gonna happen.

Pierre's stance is that the mesh diameter and open area of a 305 does not enable you physically to hold a 1% dot. Obviously, he's right...and he's wrong. It's all in how you look at it. I say yes, it does...if you are printing a lpi that works to hold that 1% such as a 50lpi on a 305. The higher the lpi, the less chance you have, but you can get closer.  Why not hold as much information in the art that you can? After all, it's about reproducing the image accurately, it's not about holding a specific lpi on a specific mesh.
Why use such a high lpi like 60-75lpi that it reduces your ability to hold fine detail information?

When you look at the actual size of a linerized 1% dot in a 50lpi, as a guess, it is going to be somewhere near the size of a 5% dot in a 65lpi. You all can hold a 5% dot much easier in a 65lpi right. Some yes, some no, but for the most part (it's easier). So, why would you think you have no chance at holding a 1% dot....in lower lpi?

Why do you want to?  because there is art image information there. Sure, it's not always needed. Note very job requires you hold down to 5-3% dots. Some jobs have halftones in it that only go down as low as 20% tone. This then, is another example of the fact that you need to focus more on holding a certain SIZE and not a certain LPI. You see, you can actually hold all of the dots in some jobs at 55lpi (on a 110 mesh). Wow's that?  Because the size of the 20% dot in a 55lpi may be very similar to or equivalent to the size of your 1% dot in a 25lpi.

[Dottonedan]

Add on,

You are seeing some people say they print 70-90lpi on very low or common mesh like 65lpi on a 230 or 90lpi on a 250 etc.  Those people are looking at SIZE of dots. Not focusing on staying within the traditional expected LPI on a specific mesh. They look at the 90lpi and compare to the mesh thread, then determine (at what % can I go down to? What LPI is going to give me awesome mifddle tone image resolution? So some determine it might be 90lpi and still hold that dot on this mesh.

So lets say in a 90pi, (on a 250 mesh), they see that they can hold the 25% dot well and nothing less. Then, then look at their shadow tones and see that they should be somewhere in the same area (70% tone) that will still hold a dot with some gain. NOW, they just don't use the same art that came out of photoshop or a sep program. They have to tweak beyond what most have ever seen or imagined. Dodge, burn, levels, curves, selections with additional fills, additional cut backs, heavier underbases, lighter top colors, adding colors where color is not, etc.  all to get a great print with this scenario.

It's all about the size. "Size does matter".  These people pushing the limits are not looking at trying to hold the 1% in a 75lpi nor the 1% in a 50lpi.  The commonality between these examples is that they are focusing on printable SIZE and not LPI.

[ABuffington]

Getting back to this after some time off.  Great stuff Dan and good advice, however for me the art and customer determines the lpi I would need.  Lots of small elements with tonal change? Higher LPI. The need to print a detailed guitar?, about all I print anymore, and get the wood grain perfect, higher LPI again.  I have seen 60lpi with good curves to eliminate anything below 5% on 135S that exceeded the quality of a 65 line:

As well as 85 line to capture stunning detail in a guitar printed with 225S baseplate and 350S on the colors.

All depends on the customer and subject matter.  I have discovered that Wasatch will break off halftones and print stochaistic below X% that pretty much fixes the moire with 2-20% dots.  The hybrid screen is accessible through Wasatch Precision Rosette and clicking on halftone properties.  There you can set the micron size of the dot and also control the % it changes at.

Al

Alan

[markdhl]

Pierre,

Please email me your test file.

mdhlexp@aol.com

Mark