Ellipse Vrs Dot shape benefit "example attached"

[squeezee]

RIPs without 'accurate screening' or halftoned in an application can only use a limited set of angles (the printer can only produce angles that are a whole number of pixels in the X&Y axes, so you can't have 20.5 x 20.5 pixels for instance)  Some angles don't exist at all, 15 degrees turns out to be irrational, it cannot be described by dividing one integer by another.  You will always get 15.1 degrees, 15.02, 14.96 etc.
If you get the angles even slightly wrong you can get moire.
Having a single angle overcomes this problem.
The application ICC profile is set up to expect rosettes, you may see a colour shift with single angles because some colour will be masked more than others.
Slightly different misregistration on the print will expose different colours which will give a different effect, you might have more cyan or magenta exposed.  It will be prone to moire if misregistered.
Rosettes are less susceptible to these variations.

[Dottonedan]

I don't see it yet. I'm open to change but but thuis far you don't have me convinced.

you may see a colour shift with single angles because some colour will be masked more than others.
Slightly different misregistration on the print will expose different colours which will give a different effect, you might have more cyan or magenta exposed.  It will be prone to moire if misregistered.

  Each issue here that you covered also equally applies to using a a rosette pattern.

Slightly different misregistration on the print will expose different colours which will give a different effect,

Same for Rosette.

you might have more cyan or magenta exposed.

  Same for rosette.

It will be prone to moire if misregistered.

Same for rosette but in my opinion, even more with rosette.

[Orion]

I don't see it yet. I'm open to change but but thuis far you don't have me convinced.

You don't need convincing Dan, just the people that output film and print your seps do.

I have seen prints using a single angle set that look great, but I prefer the four.

[squeezee]

I don't see it yet. I'm open to change but but thuis far you don't have me convinced.

you may see a colour shift with single angles because some colour will be masked more than others.
Slightly different misregistration on the print will expose different colours which will give a different effect, you might have more cyan or magenta exposed.  It will be prone to moire if misregistered.

  Each issue here that you covered also equally applies to using a a rosette pattern.

Slightly different misregistration on the print will expose different colours which will give a different effect,

Same for Rosette.

you might have more cyan or magenta exposed.

  Same for rosette.

It will be prone to moire if misregistered.

Same for rosette but in my opinion, even more with rosette.

No, with 'same angles' you have dot on dot, if you move it slightly the misregistered colour will  show like an untrapped underbase.  With rosettes, the colours avoid each other so if you have a tiny misregistration, they still aren't any different.  With same-angle you have black on yellow on magenta on cyan on white, with rosettes you have mainly one colour on white?!?
Lithoprinters and screenprinters have been using rosettes for about 100 years, I don't think that they would have missed the same-angle route if it's superior?

[yorkie]

The attachment was created using traditional angles verses all the same angles.

the top 2 images use a rosette halftone, which no matter how the color channels shift, the image retains the same hues.

The bottom 2 images use the same halftone angle. Because the dots are similarly arranges, small shifts of the halftone will reveal different dots. For process color, there is a bit of no harm, fowl, because the ink is transparent and the ink spreads, so the end result on a shirt is less dramatic than the image.

One of these days, i should update this to show line screens.

[Dottonedan]

The attachment was created using traditional angles verses all the same angles.

the top 2 images use a rosette halftone, which no matter how the color channels shift, the image retains the same hues.

The bottom 2 images use the same halftone angle. Because the dots are similarly arranges, small shifts of the halftone will reveal different dots. For process color, there is a bit of no harm, fowl, because the ink is transparent and the ink spreads, so the end result on a shirt is less dramatic than the image.

One of these days, i should update this to show line screens

I'm trying to see the enlightening concept of the picture example. What is it to show or indicate?. The top is rosette and the bottom is single angle. Got it.  I see the strobe your talking about (if i move my window scroll up and down).
Is that what your saying is the reason not to use them?  if they miss register they strobe?

[Dottonedan]

No, with 'same angles' you have dot on dot, if you move it slightly the miss-registered colour will  show like an untrapped underbase.  With rosettes, the colours avoid each other so if you have a tiny miss-registration, they still aren't any different.  With same-angle you have black on yellow on magenta on cyan on white, with rosettes you have mainly one colour on white?!?
Lithoprinters and screenprinters have been using rosettes for about 100 years, I don't think that they would have missed the same-angle route if it's superior

No, with 'same angles' you have dot on dot, if you move it slightly the miss-registered colour will  show like an untrapped underbase.

  emmmmm.  I don't think so. I've not experienced that. Remember, we are talking about tee shirts. Thats my only long term experience. I know shirt printing. Now, with that said, I also am not unfamiliar with flat stock printing. I did work in a sign/poster screen printing shop that did 4 color process. I separated the art. I know that registration shift and dot spacing is much more visible with that. But, we are not talking about what effects are more visible with flat stock.  I'm not saying that you are only referring to flat stock or any other method outside of tee shirts, but you are on a tee shirt forum.

With rosettes, the colours avoid each other so if you have a tiny miss-registration, they still aren't any different.

  It's interesting that you think this. I don't agree and can't comprehend the logic behind the statement but... who am I? I'm not scientist of the rosette.

With same-angle you have black on yellow on magenta on cyan on white,

Yes and no. What you have is the exact same "color content in it's intended location based on percentage" but just put down in two different methods ending up with the same color result.  One, being the rosette that offers 3 more interfering variables not to mentions an odd looking "rosette" pattern within my design, creating this unwanted "pattern within my art, textures and patterns".  Yuk.

Lithoprinters and screenprinters have been using rosettes for about 100 years, I don't think that they would have missed the same-angle route if it's superior

C'mon now. When anyone ever thought of printing halftones, they were thinking of doing it for what?  Paper.  So when people started printing on paper using a screen printing technique, they used the rosette pattern because why? Because that is what they were familiar with. "Hey Tom, What screen angle should we use when printing four color process using this screen printing method?  Oh, well, various angles of course, so they don't interfere with each other". They followed what everyone started doing....but it's not needed for tee shirts. Let it go.

Having a shift of any kind, showing some additional white space...or additional cyan or, or...is similar to the impact on your choices of using to much or too little amounts of lets say...black to use to replace amounts of the other ink. The choice depends on the art, the technology, the substrate and the ink type in use. As you know, I am referring to the processes called under color removal, under color addition, and gray component replacement. Typically used to decide on the final mix; different CMYK recipes will be used depending on the printing task. These are all "choices" for CMYK printing and ALL have some effect on printing the art (just like choosing to print a rosette or a single line screen, {for tee shirts}, you should choose your under color removal differently from flat stock printing as well.

We do not use the same settings as does an off set or flat stock printer.  Why is that?  Because our substrate is much different and we don't need to do certain things or we don't want the additional variables if we don't need them. This is why, for the most part, I don't follow the litho world.  I am not a peach, I am an apple, so says me.

[squeezee]

No, with 'same angles' you have dot on dot, if you move it slightly the miss-registered colour will  show like an untrapped underbase.  With rosettes, the colours avoid each other so if you have a tiny miss-registration, they still aren't any different.  With same-angle you have black on yellow on magenta on cyan on white, with rosettes you have mainly one colour on white?!?
Lithoprinters and screenprinters have been using rosettes for about 100 years, I don't think that they would have missed the same-angle route if it's superior

No, with 'same angles' you have dot on dot, if you move it slightly the miss-registered colour will  show like an untrapped underbase.

  emmmmm.  I don't think so. I've not experienced that. Remember, we are talking about tee shirts. Thats my only long term experience. I know shirt printing. Now, with that said, I also am not unfamiliar with flat stock printing. I did work in a sign/poster screen printing shop that did 4 color process. I separated the art. I know that registration shift and dot spacing is much more visible with that. But, we are not talking about what effects are more visible with flat stock.  I'm not saying that you are only referring to flat stock or any other method outside of tee shirts, but you are on a tee shirt forum.

With rosettes, the colours avoid each other so if you have a tiny miss-registration, they still aren't any different.

  It's interesting that you think this. I don't agree and can't comprehend the logic behind the statement but... who am I? I'm not scientist of the rosette.

With same-angle you have black on yellow on magenta on cyan on white,

Yes and no. What you have is the exact same "color content in it's intended location based on percentage" but just put down in two different methods ending up with the same color result.  One, being the rosette that offers 3 more interfering variables not to mentions an odd looking "rosette" pattern within my design, creating this unwanted "pattern within my art, textures and patterns".  Yuk.

Lithoprinters and screenprinters have been using rosettes for about 100 years, I don't think that they would have missed the same-angle route if it's superior

C'mon now. When anyone ever thought of printing halftones, they were thinking of doing it for what?  Paper.  So when people started printing on paper using a screen printing technique, they used the rosette pattern because why? Because that is what they were familiar with. "Hey Tom, What screen angle should we use when printing four color process using this screen printing method?  Oh, well, various angles of course, so they don't interfere with each other". They followed what everyone started doing....but it's not needed for tee shirts. Let it go.

Having a shift of any kind, showing some additional white space...or additional cyan or, or...is similar to the impact on your choices of using to much or too little amounts of lets say...black to use to replace amounts of the other ink. The choice depends on the art, the technology, the substrate and the ink type in use. As you know, I am referring to the processes called under color removal, under color addition, and gray component replacement. Typically used to decide on the final mix; different CMYK recipes will be used depending on the printing task. These are all "choices" for CMYK printing and ALL have some effect on printing the art (just like choosing to print a rosette or a single line screen, {for tee shirts}, you should choose your under color removal differently from flat stock printing as well.

We do not use the same settings as does an off set or flat stock printer.  Why is that?  Because our substrate is much different and we don't need to do certain things or we don't want the additional variables if we don't need them. This is why, for the most part, I don't follow the litho world.  I am not a peach, I am an apple, so says me.

Please look at the pictures posted by Yorkie, the lower pictures show a greater difference in colour and greater moire.  Thanks Yorkie, I was going to produce similar pictures but frankly I couldn't be arsed 

[yorkie]

I'm trying to see the enlightening concept of the picture example. What is it to show or indicate?. The top is rosette and the bottom is single angle. Got it.  I see the strobe your talking about (if i move my window scroll up and down).
Is that what your saying is the reason not to use them?  if they miss register they strobe?

At the scale of halftone dots, there is no way to ever have "perfect registration".

I encourage everybody to buy themselves a loupe. My favorite is a Paragon 10x loupe. I've owned mine for over 30 years. What i like about the paragon, is that it folds and can be carried in a pocket full of keys and change. In order to succeed in printing halftones, a loupe is your best friend. 10x is enough magnification to see what needs to be seen, but not too much.



I believe what i do about halftones, because i have seen it with my own eyes. Don't take my word or anyone else's. LOOK YOURSELF! My claim is that when the same LPI and angle is used by 2 screens, that the dots of one can hide behind the dots of the other or not hide, depending on registration. I also claim that across the entire image, that the dots will be doing one thing on one part of the shirt and something else somewhere else. With rosettes, it will be doing rosettes everywhere, regardless of registration. It makes no difference if the registration creates one form of a rosette one place and a different one somewhere else, the rosette is a rosette. If you look carefully at the image i uploaded, you can see the position of the rosette actually shifts, but still remains a rosette.

In an earlier post i mentioned textile moire. Most times that one color prints with a moire, it is a combination of the halftone to the textile. If textile moire were not an issue, round dot halftones would be preferred to ellipses. The reason i believe people use all matching angles is that the textile moire causes problems which are worse than the effects of strobing. At 22.5 degrees, elliptical dots, the fabric is least likely to moire with the halftone. If it works for 1, it works for all and as i mentioned in the prior post, the textile has other effects on ink which go past angles and dot shape and into things like spread and absorbability.

Now everybody, grab your loupe and take a look!

[Dottonedan]

At the scale of halftone dots, there is no way to ever have "perfect registration"
I encourage everybody to buy themselves a loupe. My favorite is a Paragon 10x loupe. I've owned mine for over 30 years. What i like about the paragon, is that it folds and can be carried in a pocket full of keys and change. In order to succeed in printing halftones, a loupe is your best friend. 10x is enough magnification to see what needs to be seen, but not too much.

I would not be bold enough to pretend to know anything about halftone printing if I didn't know anything about a loupe.

I believe what i do about halftones, because i have seen it with my own eyes. Don't take my word or anyone else's. LOOK YOURSELF!

 I have.

My claim is that when the same LPI and angle is used by 2 screens, that the dots of one can hide behind the dots of the other or not hide, depending on registration.

Yes, Same for rosette.

I also claim that across the entire image, that the dots will be doing one thing on one part of the shirt and something else somewhere else. With rosettes, it will be doing rosettes everywhere, regardless of registration.[/quote]  You got me baffled on this. I don't agree.

It makes no difference if the registration creates one form of a rosette one place and a different one somewhere else, the rosette is a rosette.

 Hmmmm.

If you look carefully at the image i uploaded, you can see the position of the rosette actually shifts, but still remains a rosette.

 I don't know about everyone else, but I clicked on that pic and it blew up and became even blurrier to me than when viewed at the snap shot size. I can't see any "detail" in it to tell anything about the dots.

In an earlier post i mentioned textile moire. Most times that one color prints with a moire, it is a combination of the halftone to the textile.

again, I might be slow some how when it comes to comprehending what you are saying here. None of this is my experience and I've got allot of it. My customers and shops where I've worked have printed FINE halftones of black ink on white tees allot...and with no moire issues. My typical halftone is 55lpi with 22.5 degrees using an ellipse dot shape. We can even go 60lpi safely with most customers. Now, I can use a round dot or even a square if anyone wishes but with no moire on any of them.

If textile moire were not an issue, round dot halftones would be preferred to ellipses.

ummm.  see pic at beginning. "There is a reason it is not the "preferred dot". The effect in the initial post here does happen no matter what substrate. It's not the textile that effects this.

The reason i believe people use all matching angles is that the textile moire causes problems which are worse than the effects of strobing.

Moire is not all that common. If you are getting moire, it's because you're making a mistake in your process. Not what shape your dot is...and it's not always "at what angle" as a reason for moire but most likely, it's to do with all of those varying angles. Keep those boogers at the same angle and it's golden. If that were the case, someone who does have good working varying screen angles for CMYK would not experience moire...and we all know that moire can happen at any time if you do not have everything in tight.

At 22.5 degrees, elliptical dots, the fabric is least likely to moire with the halftone. If it works for 1, it works for all and as i mentioned in the prior post, the textile has other effects on ink which go past angles and dot shape and into things like spread and absorb-ability.

 Ok.  I'm with ya here. I agree. We are now firing on the same brain waves.

Now everybody, grab your loupe and take a look!

Been there. Done that. Got the tee shirt.  Haha. get it?  Got the tee shirt?  oh brother.

You know, what really bothers me is not that you 2-3 agree or don't agree. It's that you think that the old way is the only way or the "right way".  You know how to determine good art?  It's based on making the sale. Good art to one is an opinion.

Good halftone angles apparently is an opinion also.  If a single angle didn't work, or wasn't good enough or isn't the right way, then how is it that so many people bought hundreds and hundreds of thousands, no. Scratch that. ....42000.00 units per week and 2.2 million per year (conservative calculation) on average, using my single line screen of using my 22.5 degrees? not to mention winning 2nd place in Sim process using a single line screen angle? Just asking.

I think I'll stick with my 22.5's    You can't argue with smooth production and big money.

[Orion]

So the four angle set does not work? I guess millions of people are gonna want their money back that they paid for their shirts when they find this out. No one said you were wrong Dan, sorry if we offended you in any way.

[inkman996]

My take when I look at Dukes example I do not see the second rosette as any blurrier at all, and all the colors look the same no shift.

The bottom set has a distinct difference between the two and not for the good. Thats my opinion for what its worth.

[squeezee]

Sim process is done with opaque inks, the difference in colour with misregistration is going to be greater?

[Dottonedan]

So the four angle set does not work? I guess millions of people are gonna want their money back that they paid for their shirts when they find this out. No one said you were wrong Dan, sorry if we offended you in any way.

To imply that I am saying it doesn't work, would be putting words in my mouth in hopes to do the ole switch-er-oo.  No. It does not mean that is does not work. That would be ridiculous to say. In fact, if you go back into my post (Don't bother, it's not there).  You would see that I never said that at all. I am simply saying, don't bank on the old "rosette" theory as a MUST HAVE. in fact, all I am saying is that. "For tee shirts, using multiple screen angles and desiring the "rosette" pattern is not needed for screen printing on tee shirts. and I prefer the single line screen.  It's you guys that are desiring to show me different and well, I've not seen any real proof at all yet. I am open for doing it the best way and the easiest way. Sometimes those two aren't always the same thing but I'm open to changing. I am simply looking for the reason sot want to do so.  So far, All I have seen as proof is that EVERYONE use to do it and so should we.  I say What for?  I don't want little rosettes in my solid (intended to be a consistent looking flat area) of color and I don't want the hassle of aligning in register, 3 additional angles.

I am not very experienced at the screen angles of any other process...but I will also say this, even in offset/litho The "Rosette" is not a requirement. You see, you can even print CMYK using stochastic dots. As you know, those have no rosette pattern or any pattern at all. They are frequency modulated and they were also "created by" the Litho/offset industry.

I know I sound like an arrogant Gluteus maximus, but I guess confidence often resembles arrogance. I don't mean to be offensive if I sound that way. I prefer to call it being Passionate about what I do. You all know that. I see it in you as well.

[Dottonedan]

Sim process is done with opaque inks, the difference in colour with misregistration is going to be greater?

Actually, even the term "Simulated" process signify the use of translucent inks. The regular inks must be modified to
A, go through higher mesh to print thinner dots,
B, go through higher mesh to  assist in laying the inks down thinner so as to aid in blending.

The ink manufacturers even sell inks (specifically for) the simulated process printing. You can come close to these by just adding some extender or clear base additive to help thin out these regular inks so that they can do both A and B.

To answer your question, I don't know.
The miss alignment of multiple screen angles plays the same result (in varying degrees) as does a miss registered single line screen (over all).  Here or there, you will have a tad bit of white showing in one place or another. Often times, (more so than not), you are talking about weather the white shirt is showing over here at 25 microns or over there at 12 microns or 100 microns on the other side.  That can be the same in a rosette pattern as well as a single line pattern.  The theory that the single line pattern just puts the dots on top of each and does not show the detail of what a rosette would, does not hold water. You are (intending) to blend these inks/dots. So you really want them to blend over top of each other.  Where white is to be, you have no dots, where white is to be just a little bit, you have littler dots and so on. Where the print is to be pastel, you will have very small (highlight dots sized) percentages of CMY and sometimes K with a little white shirt showing (like you would with the rosette pattern).

In addition to all of that, I would also say that it's even BETTER if the dots blend together sooo much that you no longer even see a dot, just a continuous tone like photo quality. You can come close to that using 350 mesh and stochastic.