Resising Changes Colours When Using Partial Transparency X8

[flagpole]

So by way of an example:

If you download this file http://uploaded.net/file/cgt9y1nn/examp ... r.pspimage or
https://drive.google.com/open?id=0B3_Jd ... XlPWHR5eE0

And resize it 50%, 150% it doesn't really matter you'll see a shape appear.

What appears to be happening is on the top layer where there is AA using partial transparency the resize algorithm comes along and can't find the colour data for the transparent area and treats the null as 0,0,0 ie black.

I've reported this problem before under an old version and it was fixed

I'm on X8.0 BTW

[JoeB]

I'm not sure what you're saying. What I see is an image with 2 layers. The bottom layer is white and fills the image. The top layer is also white but is a smaller rounded rectangle, rotated at an angle, surrounded by transparency. I don't see AA. I resized 150%.

[flagpole]

Sorry I mean actual resize. Not just zoom in.

[JoeB]

Sorry I mean actual resize. Not just zoom in.

I did actual resize using the Resize tool and dialogue.

[hartpaul]

This is one of those odd occasions that most people would not see. As how often would one place a same colored object on a transparent layer layer over another same colored layer and then want to resize it before merging.
If you merge and resize then you have no problems.

I did not get 0,0,0, black but 235,235,235, where the algorithm is trying to maintain partial transparency. If there is no partial transparency (no diagonal lines no curved lines ) then there is no problem on resizing.
As well if the image is planned in advance then there should be no need to resize before merging all layers.

[flagpole]

Sorry I mean actual resize. Not just zoom in.

I did actual resize using the Resize tool and dialogue.

So if you resize it in x8.0 it looks like this:

exampleoferror.png (2.05 KiB) Viewed 7353 times

You see how the areas with partial transparency turn grey?

[flagpole]

This is one of those odd occasions that most people would not see. As how often would one place a same colored object on a transparent layer layer over another same colored layer and then want to resize it before merging.
If you merge and resize then you have no problems.

I did not get 0,0,0, black but 235,235,235, where the algorithm is trying to maintain partial transparency. If there is no partial transparency (no diagonal lines no curved lines ) then there is no problem on resizing.
As well if the image is planned in advance then there should be no need to resize before merging all layers.

The problem is i work a lot on images not on a back ground.

When i say 'black' what i think is happening i think on the border is that it's treating the area with no colour as if it were black, and at the border where it's blending the two colours you get greys.

[flagpole]

Image3.png (6.02 KiB) Viewed 7350 times

This is basically what is happening.

[flagpole]

I'm struggling to understand why nobody else has noticed or is bothered by this

For my work it's crucial. I'm having to resize things in PS. This happened once before and was fixed, I'm going to have to go through the patch release notes and see if i can figure it out.

meanwhile.... you see the sort of grey border on my sword?

example.png (10.76 KiB) Viewed 7132 times

[JoeB]

Is it possible to get the original that you resized? The sword on the left looks like it has exaggerated artifacts along the edge of the blade where it's looking like a grey border (assuming that's the area you're talking about). If that's the case, it may be the Resample Using option you're choosing and you might want to experiment with the other options in that dropdown and see if anything else does a better job.

[flagpole]

Is it possible to get the original that you resized? The sword on the left looks like it has exaggerated artifacts along the edge of the blade where it's looking like a grey border (assuming that's the area you're talking about). If that's the case, it may be the Resample Using option you're choosing and you might want to experiment with the other options in that dropdown and see if anything else does a better job.

Fo shizzle

though once they were on a white background i pixel resized 'zoomed' them to make the effect more apparent. From what you said earlier i believe your version doesn't do it.

[JoeB]

I'm still not quite sure what you did but you seemed to say that you used pixel resize to make the original image smaller and then posted a zoom of the result to make the effect more apparent? Do I have that correct?

In any event, I took your original from the last post and resized it down to a height of 200 pixels, using the various options. Pixel Resize gives the worst results by far in terms of jaggies, as would be expected, but does not show the grey artifacts with the jaggies. I found Bicubic gave the best results, with the smoothest outlines and a bit of barely discernible greying of any jaggie artifacts. Bilinear was almost as good with those factors. Weighted Average (which is also what would be used if Smart Size was the selected option) was again better than Pixel Resize but not as good as the other two and showed more visible greyish artifacts along some of the edges similar to the right hand image in your first post.

I don't know if my testing was actually addressing the issue you were raising. But I do suggest that Pixel Resize is never a good resizing option for images with gradations and/or irregular shapes.

[flagpole]

No no. I just used pixel resize, after i had completed everything to effectively zoom in for posting the image to the forum.

[JoeB]

No no. I just used pixel resize, after i had completed everything to effectively zoom in for posting the image to the forum.

Well then I'm afraid I don't understand the problem or don't see the same problem.

The 64sword image you posted is 267x695 pixels. That image, to me, has no grey border at all that I can see, even when zoomed 1000%. Without a more detailed explanation of how you are getting the problem you are seeing I'm at a loss. For example:

1) Do you see the grey border on the same 64sword image that you posted for us? If so, then that's something I would be unable to explain because, as stated above, I simply can't see it even zooming in 1000% to view it. So I wouldn't be able to add anything more to try to help.

2) On the other hand (if my first point is incorrect), if the 64sword image you posted is not the one that you see showing a grey border, then what resize steps did you take with it that resulted in a grey border becoming visible to you?

3) The first image you posted has 2 images of the sword, the one on the left showing grey along much of the jaggy parts, the one on the right not showing any grey. I now realize that I do not have any idea what that image is supposed to be telling me given that the two swords look identical - i.e., show identical jagginess indicating both were resized to the same size - except one has grey and one doesn't. How did you get one of them to show the grey and one of them not to?

Without much more step by step info I'm simply at a loss to figure out what you are trying to tell us. I'm not sure if anybody else understands either because nobody else has posted anything in response to either your or my posts.

[flagpole]

1) no, no grey border.
2) keeping the sword on a transparent background and then resizing by any method, smart size, bilinear, bicubic
3) the one without the grey border was first put on to a white background, then resized. this prevents the grey border. because of the reason i stated above.

I think you're being confused by how jaggy the two sword picture is. it's just a zoomed version of this:

sample.jpg (17.87 KiB) Viewed 6969 times