Halftone dot testing

[Screened Gear]

After the last post on film making and dots I got to thinking what do my dots look like in each step of the process. Well I got a Microscope and did some testing. I thought I would share my findings.

This is a 4 color process print. It is done at 55LPI all angles at 22.5 on 305 mesh with unions inks.

[Screened Gear]

This is the area I tested

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This is the film for that area.

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this is the shirt in that area

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This is that area with the film overlaying the shirt. The film is set just under the dots on the shirt.

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This is the film in that area at 800 percent

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This is the printed dots at 800 percent (not the same dots from the above pic)

The reason I did this was to find out where I need to improve. I knew before I did this that my film printer did not make nice round dots. I really wanted to know how that affected the final print. In the below image you can see the dots are more affected by the weave of the shirt fabric than my badly printed film dots. I always hear other printers say you will lose your smallest dots in the weave of the fabric. I never thought that the weave would mess with the final dot size and shape as much as it did in the above image. Remember this is a very tiny spot and the dots are very small.

I am interested in hearing what others think. I am open to any advice on improving. (I know the registration in the image is off by a hair or two.)

Thanks

Jon

[blue moon]

Nice looking print there! Nice transitions and good gradients.

OK, I had to go and check to make sure I am not talking out of my a&*. Our dots look better when printed. Not a huge difference, but just enough to be able to tell. I only looked at one shirt, so that might not be a good example, but it seems that better films will give you a better dot (damn, can I state the obvious!!!).

Better dot is the biggest difference between the prints that are coming in the first place and the stuff we are submitting. The dot quality of the winners is absolutely amazing. And while I thought that an improvement in one area is what's holding us back from achieving those, the truth is, absolutely everything in our process needs to be improved to print at that level.

So Jon, new printer next, than back to the drawing board and calibrating everything to work with it. 'looking at the print, what is the smallest dot you are printing?

pierre

[Screened Gear]

Smallest dot?? I have no Idea. How do you measure that. I guess I could print out 55LPI squares (1 percent dots, 2 percent dots, etc) than then measure the dots to the shirt and see what size they are? With dot gain I could be printing one percent dots and they look like 2 percent dots. Let me know how you do it.

[blue moon]

Smallest dot?? I have no Idea. How do you measure that. I guess I could print out 55LPI squares (1 percent dots, 2 percent dots, etc) than then measure the dots to the shirt and see what size they are? With dot gain I could be printing one percent dots and they look like 2 percent dots. Let me know how you do it.

print the squares and then print them on the shirt. See which on prints without interference from mesh. That is the smallest dot you can print. Then if you want to, send me some swatches and I'll take the readings. Unfortunately, the readings are usually not very reliable. You could just compare the printed dots with the ones on the film.

pierre

[Screened Gear]

what size dots? 55LPI? I will have to try that. I know one of the biggest parts to get the 1-5 and 95-99 dots has to be your exposure time. If you over expose even a little you can close a your 95-99 percent dots and it will not wash out. If it is a free standing dot (your 1-5 percent dots), if your time is one second too short it will wash off. I have 2 305 screens I can test and see. I have my times close but I don't think they are good enough to do more than 3 or 4 percent. I also don't think my film is dark enough to hold that dot. I will see if I can get it on in the next day or two.

[blue moon]

what size dots? 55LPI? I will have to try that. I know one of the biggest parts to get the 1-5 and 95-99 dots has to be your exposure time. If you over expose even a little you can close a your 95-99 percent dots and it will not wash out. If it is a free standing dot (your 1-5 percent dots), if your time is one second too short it will wash off. I have 2 305 screens I can test and see. I have my times close but I don't think they are good enough to do more than 3 or 4 percent. I also don't think my film is dark enough to hold that dot. I will see if I can get it on in the next day or two.

if you can hold the 5% dot at 55lpi, you are doing better than 98% of the shops out there (from what I gather). Most that are actually printing halftones are probably in the 7-8% range, maybe as high as 10%.
We can hold the 3% at 65lpi on 330 "S" mesh, and that is just about the limit of the mesh (and my wallet! It took over a thousand hours of R&D and about $10k to get there). One and two percent can open up, but they will not be clean due to the limitations of the mesh. There was a good discussion going on about it last year in the screen making section. On the other end, anything over 90% is probably a moot point due to the dot gain. I think we are right around there, maybe 92% at the most.

I'll return a favor. The "good-bad" idea on the films we stole from you and are now using on all the prints. But we also added the little halftone grid with a 5, 10, 25, 50, 75 and 95 percent squares. This way we can look at them and see what's going on. I have seen different films produce different results.

pierre

[ScreenFoo]

It's a less than scientific way of doing it, but if you take a picture like that with a ruler or calibrated scale of some sort next to it, you can get a rough scale of how big the dot is by changing the image DPI, and using the selection tool in photoshop.

I was excited when I saw my 5, 4, 3, and even most of the 2% dots resolving and printing, until I realized my inkjet on the matte setting was gaining nearly a hundred percent on film with the tiny dots.     

[blue moon]

I was excited when I saw my 5, 4, 3, and even most of the 2% dots resolving and printing, until I realized my inkjet on the matte setting was gaining nearly a hundred percent on film with the tiny dots.   

right there with you! Two years ago we had 3% fully open and 1 and 2 about 90%. I could not believe it! Year later I checked the dots (after finally getting a densitometer) and the 3% was actually reading 7% on the film!!! No wonder they were opening! We are at about calibrated 3% now and it does not look like it will get any better any time soon.

pierre

[admin-tone]

Great post. I am loving these post. Some of these post are starting to get to the nitty gritty of it all.   Well,  I might be a little biased about dot tone subjects.