Pixelated image after changing canvas size in Photoshop

[Guest]

- I opened a PNG file which has some transparency and is 401x82 px.

- I wanted to add empty space above and below, to get the width/height ratio I wanted.

- I used  Image > Canvas Size  to change the image size to 401x111 px.

- This worked, and it extended the transparent background.

- As far as I understand, this should not stretch or affect the image content itself (or pixelate it).

- I saved as PNG, using defaults.

- It came out more pixelated than the original.  I'm viewing it at the same size as the original.

I'm using Adobe Photoshop CS5 v12.

[c.pfaffenbichler]

- It came out more pixelated than the original.  I'm viewing it at the same size as the original.

Please post the two images or screenshots of both taken at View > 100%.

[Guest]

Here are the 2 images.  I enlarged them beyond 100% to make it easier to see the pixelation.

[c.pfaffenbichler]

I specifically asked for screenshots taken at View > 100% (or the images themselves).

And please include the document bar in which the name, color mode and magnification is indicated in the screenshots.

[Guest]

Ok, here are screenshots.  The last screenshots I sent were the images opened in Irfanview after saving the file as PNG.  )I combined the before and after into one image.)

Below, I will attach the original image at 200% with the full window in PS.  I found out how to change the default transparency background image.  The pixelation on the red swoosh looks worse with the light background, so I will send that first.  The second image is just after I changed the transparency background to dark.  The third image is after I increased the canvas size (10px on top and bottom).  The quality looks low even before I increased the canvas size, so I don't even know if that's relevant anymore.

The image was only 401x82px to start with, so maybe it's supposed to look bad at 200%.  The bottom line is that the resulting PNG looks worse than the original PNG, outside of Photoshop.

[c.pfaffenbichler]

The image is Indexed Color Mode so you probably saved as png-8 instead of png-24.

Anyway: I've had it; there seems to be no screenshot of the original image and what’s so hard about View > 100%?

Good luck!

[Guest]

The view is 200% isn't it?

[Guest]

The original image was a 8 bits/pixel PNG.  I saved the result as 24 bpp.  Could this be the problem?  But the original looked ok.

Oh, when you wrote "View > 100%", maybe you didn't mean "View GREATER THAN 100%".  Maybe you meant ">" as in a menu command.  I could send it as 100%.

[Guest]

[Mike_Gondek · Accepted solution]

I copied your settings PNG24, Bicubic Smoother, increased canvas size and  did not get that result. Below is what I got. Open image below in Photohsop.

Earlier you showed examples with indexed color, which leads me to suspect you used PNG-* settings that reduced colors.

I do not see your issue having to do with increasing canvas size, but the png settings you used.

The 2nd image you posted ProtectionPlus21-resized1.png, is RGB not indexed, but the transparency of any colors has been removed. The pixels are either 100% or 0% transparent.

You are using an older version of Photoshop CS5, try PNG-8 with atleast about 24 colors for this image, as PNG-24 might have some bugs.

[Guest]

- Mike, the image you posted looks fine.  Since you resized the canvas to the size I need, I can just use your image.  So thanks.

- I'm happy to continue this discussion, if it helps other people or educates me.  But, because I'm using an old version of PS, maybe it's not worthwhile.

- What's the etiquette here?  Should I mark anything as Correct Answer?

- >I do not see your issue having to do with increasing canvas size, but the png settings you used.

- That seems likely.

- >The 2nd image you posted ProtectionPlus21-resized1.png, is RGB not indexed,

- Well, I saved as PNG-24, so maybe that forces it to be RGB.  Not sure.

- >but the transparency of any colors has been removed. The pixels are either 100% or 0% transparent.

- A few questions: How can I see this info?  Was this true of the original image?  Would this cause pixelation?

- >You are using an older version of Photoshop CS5, try PNG-8 with atleast about 24 colors for this image, as PNG-24 might have some bugs.

- When I saved, I just used the default PNG-24 settings.  I tried just now saving using PNG-8.  I used the default of 128 colours, and Matte=none.  It has Dither=88%, while you used 100%.  The saved image still looks bad.  I changed Dither to 100%, and it's still bad.

[Mike_Gondek]

Great. Can you please choose an answer as correct to close this post, so noone else puts time into this post.

I as the wise Herr c.pfaffenbichler am tapping out.

[c.pfaffenbichler]

Did you save as png-8 or png-24?

[Mike_Gondek]

After you added the canvas size, did the preview look bad.

     No - Then something in how you made the png corrupted this.

     Yes - Not sure  what could be the issue yet as this looks worse than align to pixel grid issue

In CS5 if I remember correctly,  File >> Save for web , you can see the preview before you save, and is better for making web images. In newer verisons is  File >> Export >> Save For Web

Please post the original and final files (using dropbox, google drive or similar), so we can see if you have live type antialising issue or etc.

[Guest]

I did use Save for web.  I just noticed that as soon as I open the original image in PS (via drag & drop) and view it at 400%, it looks bad already, before I changed the canvas size.  If I view the image in Irfanview and enlarge it the same way, it looks fine.  The original file is a PNG.

[Mike_Gondek]

If you used save for web, why would you not share with us your settings??? Hard to review with the transparency checkered pattern shown, might be better to post the original image and he after image.

[Guest]

[Guest]

Before

https://drive.google.com/file/d/1bJaW8XVCLsQ_UgpCyM3OjUnLHDcperWk/view?usp=sharing

After

https://drive.google.com/file/d/1_lnPjxSo84B-D7J9B1_0YjB25YnLWI38/view?usp=sharing