# Transparency - Photoshop?



## Stitch-Up (May 26, 2007)

Hi guys

Looking for some advice .

A customer sent me an image in Photoshop .psd format to be printed on a dark red t-shirt.

Here is a small part of the image clipped' from Photoshop.










I thought, pssibly incorrectly that the transparent nature of parts of the image would allow the colour of the shirt to show through. To illustrate my point, I created a new layer in Photoshop and filled it with a dark red colour and placed the layer behind the artwork. The result - it just made the colours of the artwork solid! Even if I created a black layer, it didn't show through as I thought it would.

I printed the artwork onto a dark red shirt and the white layer was very grainy, more or less as I'd have expected it to be due to the transparent nature of the image.

So, what am I missing here? Why in Photoshop did it not allow the background layers I created to effect the image in the way I thought it might? Black, white, dark red or whatever, the only effect was to make the image colours (top layer) opaque 

I'm probably being completely dumb


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## dmfelder (Oct 25, 2008)

Is there a way you can post the PSD file?


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## weprintdotorg (Mar 31, 2011)

How are you printing these shirts? Screen Printing, Dye Sub or Heat Transfer? I would think that the only way to truly keep the transparent look and allow the shirt color to show thru would be to print on a clear heat transfer paper or use water based - process color screen printing inks, which have a really thin opacity limit to them.

Oops, Sorry. Just saw that this post was in the DTG threads.


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## shughey (Jul 22, 2010)

Are each of the different colored shapes a layer..? I am sure they are.

What is their opacity percentage? Looks like they may be 90% or so...just guessing?

At an opacity of 85-90% you would see the transparent background as you show above...but...when you place a solid fill behind them it won't change the colored shapes that much.....not enough maybe to notice it.

If you had 3 different background layers...red,white and black and you turned each one on and off you might see a slight difference in the color in the most transparent areas but you won't "see" the background color at all.

So if the opacity is 85-90% you really won't see any of the background poking through...it will just make it look solid...which is what you are you doing by turning on a background right.


Meaning if you have one of those shapes...say...the light blue one...and it's opacity is 85%...when you turn on a solid background on behind it...well you just made the transparent area look solid...because...you backed it with a solid fill. 

Spiritually speaking you are only adding a small percentage of solid color to the colored shapes by doing a background fill and it won't have a huge effect other than making them look solid...but they are still transparent.

Turn one of the layers opacity down more and you would see a greater effect.

Now print it on a black shirt with a white underbase and the more transparent areas probably look like poop with alot of white showing through?


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## dmfelder (Oct 25, 2008)

I was thinking the same thing. It's seemingly an alpha level thing with a variation in fill opacity, but there is no mention of individual layers, so maybe there was some opacity tweaking , then the layers were merged. 

Anyway, not sure what more help we can provide without the art file.

Cheers.


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## Stitch-Up (May 26, 2007)

Hi guys and thanks for the replies.

I can't post the original artwork just yet until I get permission. There are no individual layers, it looks like the layers have been 'merged' if that's the correct description!


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## shughey (Jul 22, 2010)

One quick question. Is it causing any actual problems when you print on a shirt? Or was the question more from a curiosity end?

Was not sure if yo were trying to make them opaque to print on a dark shirt and not have so much white underbase showing........?

The person who created the file had to merge the layers...as I would think each shape was a seperate layer as PS creates a new layer when using a shape tool. They probablt set each layers opacity level then just merged them all.


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## Stitch-Up (May 26, 2007)

This is the curious thing Scott. I've only tried printing on a red shirt and the result was bad!

My theory is, because the colours are not opaque, less white would be printed than if they were. I watched it print and the white layer certainly didn't cover the red of the shirt very well. I sort of expected this as in the image, the background isn't covered fully - you can clearly see the checkerboard/background.

I've since saved the file in jpg format and of course this has removed any transparency rendering the colours as 100% opaque. My guess is this will print a lot better with the white layer blocking out the red of the shirt. I'll let you know.

Cheers

John


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## shughey (Jul 22, 2010)

That is what I would have expected...and what I see when printing transparent images on a white underbase where the RIp prints the white ink layer relative to the density of the color layer.
Transparent color layers , to me, are always a challenge to print with a white underbase.....and get them to look great. Some RIPS seem better than others though.


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## jfish (Feb 26, 2010)

you could maybe try making a fine halftone of the shape so it would have somewhat of a trans look but makesure the choke is adjusted right so the white under base doesn't show outside the color


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## Stitch-Up (May 26, 2007)

I print shirts for a few other designers who use transparency a lot for distressing the final print - it works well for that as the print has that faded.broken look.

This is not the result of poor pretreatment 

Here's an example


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## cavedave (Dec 5, 2006)

The Apha layer (that is a greyscale image that determines the level of transparency in any given area) is typically used to determine how much white goes down and allos the shirt color to blend with the image.

Your problem is you are printing onto a dark red shirt, for example
Dark Red in CMYK = M+Y then add the cyan and you have black (or more commonly mud), same with the blue area as Blue = C+M and add M+Y you get more Mud.
The Red and Magenta areas should just get much darker version and the Yellow will get dark but at some point you read 100% saturation when you prinyt the primaries.

So transparency used on an image like this for a red shirt doesnt make any sense, may be on a light colored shirt (say a pastel yellow).

I would ask the customer what he expects, my guess is the transparency was used to build up the image and he just wants the color opaque on the shirt.

Best regards

_David


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