How Did Someone Save This T-Shirt With Multiply FX Embedded In It As PNG File?

[grpetz]

I have a t-shirt design program installed on our website and I need to create an overlay t-shirt that has the transparency like this one shown so customers can add various colors to it. The image below is from the demo of the t-shirt program, however I need to make one from a Gildan tee.

It seems to look like the image uses a multiply effect that is embedded in the image? When I open it in Photoshop I can zoom in and see the transparency showing through the shirt. The shirt takes the color of whatever is underneath it as a base layer, even without applying a multiply fx. How was this done?

I've tried using the background eraser on a white shirt, but not able to produce the result that way and applying opacity to a t-shirt image doesn't do the job either.... ... thank you for helping. Really appreciate it.. Gary

 

[thebestcpu]

Hi Gary
A PNG file can contain image pixels and as well a separate channel representing transparency.

In the image below I separated out the pixel information from the transparency channel information to show you them separately.

Image pixels is the left half of the image (yes their that dark) and the transparency channel on the right:



The illusion that the image looks white has to do with the default background of the browser using white as the background underlay.

Also, the transparency/opacity is not uniform across the image as shown by the transparency channel on the right.

So those are the components of the image that create the effect you are observing. So the real question to be asking may more be: How do you create such an image with that type of transparency in the first place?
If I knew off the top of my head I would give that answer too yet others on the forum might have that answer.

 

[grpetz]

Thank you for that explanation.. that helps me understand PNG a lot better. I'm new to this forum and. I did get a reply from Mr Tom (Thank you Mr Tom!)... and his answer gave the total solution... I just don't need to do steps 8 and 9... since our t-shirt design software online is adding the base layer color already... I'll post his response below... I don't know why I don't see it here on the forum topic as a reply but I got an e-mail reply that he posted? Anyway here is the solution and thanks again for the help! - Gary

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You could try doing this by using channels.

1. Copy the original image layer.
2. Add a hue / sat layer, set sat to -100.
3. Merge down this layer.
4. From the channels panel use Ctrl + click thumbnail of any colour channel...they are all the same so it doesn't matter which.
5. Back in the layers panel create a new layer.
6. Invert the selection.
7. Fill with Black.
8. Deselect and add a new layer below this 'Black' one.
9. Fill this layer with the colour you want.

You can add any further adj layers to the black one enhance its appearance.

Regards.
MrToM.
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[MrToM]

I deleted the post because it wasn't correct, well, what I wrote was correct but it was only half the solution.

Having said that, if it works for you then fine, I'll leave it at that.

Regards.
MrToM.