Blurry Jpegs

[Guest]

My Jpegs appear blurry and I can't figure out why... I've never had this problem with Pixelmator or Photoshop. I tried using the Bicubic option instead of Bilinear as it suggested in one of the tutorial, it seemed to make a difference earlier but now it doesn't??? Using Affinity has been very puzzling so far... it seems as though I would need to be an expert Graphic Designer to understand how to use it.

Also, what is Resampling?

[R C-R]

Resampling increases (upsampling) or decreases (downsampling) the number of pixels in an image by applying an algorithm like Bilinear, Bicubic, or Lanczos interpolation to its pixel data. Which algorithm works best depends on both the image & if it is being upsampled or downsampled.

[Guest]

Do you think Bicubic is the best option? I always do downsampling and nothing special about the image, except that it's a drawing not a picture.

Thanks for the explanation. :-)

[lepr]

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[lenmerkel]

Honestly, the "best" option is the one that gives you the results you like. I recommend trying each option for one particular image and see which works best for you. Sometimes it needs a little trial & error. 

 

Here are some resources that explain the differences between the various re-sampling methods. They all refer to Photoshop, but the principles are the same.

 

https://support.esri.com/en/technical-article/000005606

http://www.dummies.com/software/adobe/photoshop/how-to-resample-images-in-photoshop-cs6/

https://www.photoshopessentials.com/essentials/resizing-vs-resampling/

http://www.graphics.com/article-old/fundamentals-resampling-photoshop

 

[Guest]

I tried all the resampling methods and the best one was Lanczos 3 (separable), but all of them made the image a little blurry... even at a high resolution.

What's going on? Why is it so complicated to export a file as a jpeg without making it blurry?

Thanks for all the links lenmerkel

[Guest]

So if I uncheck resampling the image is clearer but for some reason I can't change the size of the image? I put in the dimensions I would like, then once I uncheck Resampling it deletes the dimensions I just entered??? Not only that, the dimensions are blocked and I cannot change them again. What's up with that?

[R C-R]

37 minutes ago, JosianeHoude said:

What's going on? Why is it so complicated to export a file as a jpeg without making it blurry?

Because it is complicated. There is no 'one size fits all' conversion method that produces no blurring at all. It depends on the image content, the final pixel resolution of the export, & the amount of compression used. That is why trial & error is required.

 

27 minutes ago, JosianeHoude said:

So if I uncheck resampling the image is clearer but for some reason I can't change the size of the image?

The reasons for that are explained in the articles @lenmerkel provided links for, particularly the last two.

[Guest]

But it wasn't a problem when I used Photoshop and Pixelmator, I didn't have to study boring technicalities to make a jpeg export.

Thanks for your help though, I'll take a look at the articles.

[lenmerkel]

1 minute ago, JosianeHoude said:

But it wasn't a problem when I used Photoshop and Pixelmator, I didn't have to study boring technicalities to make a jpeg export.

Thanks for your help though, I'll take a look at the articles.

 

Well, if it were just a matter of exporting a jpeg, it would be simpler. However, as you are resampling, then as R C-R says, it does get complicated. With resampling, you are either removing pixels (downsampling) or artificially adding pixels (upsampling). Each process requires different algorithms for best results, and while the details "might" be boring, understanding them will help you get better results. Go ahead and read the articles first, then come back for more help if you need it.

 

BTW, would it be possible for you to reply and attach a sample "before" image, and briefly describe what you're trying to do? E.g. "I want to downsample the image to exactly xxx pixels by yyy pixels, and save as JPEG with 95% quality (compression)". 

[Guest]

I still don't understand why I've been using Photoshop and Pixelmator for years and never had to study this stuff... But I agree that having a better understanding of it will probably help me get the results I want. I kind of thought that using a software application would help you not have to deal with these complications, like their job would be to have it figured out for the user so dealing with the app is not complicated and frustrating. So far I'm getting a feeling of bad user experience from Affinity Photo and I'm really disappointed, but it could be that I just need to get used to a new software. :-S

I'm not going to attach a sample image, but what I want to do is very simple. All I want is to export an Affinity Photo file that's about 300 in resolution into a jpeg at 72 of resolution and a size that's suitable to view on the Internet (roughly 500 to 600 px). The most important is that I want a clear image, so I've been keeping it as a "Best Quality" jpeg.

Thanks for your help!

[R C-R]

5 minutes ago, JosianeHoude said:

The most important is that I want a clear image, so I've been keeping it as a "Best Quality" jpeg.

If that is your goal, avoiding jpeg & exporting to the PNG format instead might be a better choice, particularly where transparency is desirable. But it will depend on the image, the number of colors it includes, how important small file size is vs. rendered quality, & so on. There is no 'one size fits all' approach that will work best for everything, nor is there a way for software to automatically determine what is most important to the user.

[Alfred]

1 hour ago, JosianeHoude said:

All I want is to export an Affinity Photo file that's about 300 in resolution into a jpeg at 72 of resolution and a size that's suitable to view on the Internet (roughly 500 to 600 px).

 

If you’re exporting for use on a web page, resolution is irrelevant. Just set whatever pixel dimensions you require.

[R C-R]

39 minutes ago, Alfred said:

If you’re exporting for use on a web page, resolution is irrelevant. Just set whatever pixel dimensions you require.

Technically, the pixel dimensions of a raster image define its resolution; what is irrelevant for web pages is DPI.

[gdenby]

I uninstalled Photoshop Elements a week or so ago. Due to a system problem, all image viewing would default to using Photoshop, despite me repeatedly changing all files to Preview. (All text files opened with Numbers, go figure) Haven't restored it yet, so I couldn't test that. But I do have Pixelmator. Doing down sizing in it and AP both cause anti-aliasing. I'm supposing that is the blur JosianHoude is talking about. Pixelmator's anti-aliasing is more moderate than Affinity's. Not quite as noticeable, but its there if one zooms on the pixels.

 

The anti-aliasing can be reduced by a subsequent unsharp mask, tho' that causes some hue intensity shifts.

[v_kyr]

PSE does quite Ok here when using bicubic sharper for image downsizing, though not as good as GraphicsConverter which when used with best interpolation settings gives finer results.

[lenmerkel]

4 hours ago, JosianeHoude said:

All I want is to export an Affinity Photo file that's about 300 in resolution into a jpeg at 72 of resolution and a size that's suitable to view on the Internet (roughly 500 to 600 px). The most important is that I want a clear image, so I've been keeping it as a "Best Quality" jpeg.

 

As Alfred has said, your "300" and "72" numbers are DPI, and that is irrelevant for the web. It is only a hint to printing software that you want to physically print that number of pixels per linear inch of medium (e.g. paper). Changing an image's DPI does not change the number of pixels in an image - it only changes that hint. It is essentially just metadata (which applications can choose to honor or ignore), and is one of the most widely misused and misunderstood terms in digital imaging. 

 

As R C-R has said, it is the actual pixel dimensions that defines the resolution of your image. A 1500px by 1000px has exactly the same resolution, regardless of what you set the DPI inside it.

 

I understand you don't want to upload a sample image. What would be helpful is if you could let us know the pixel dimensions of your original image, and the new dimensions you want to create in your downsampled image. For example, original is 6000px by 4000px, desired new image is 600px by 400px. 

[lepr]

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[Guest]

Thanks everyone for all your help. 

I read the articles suggested by Lenmerkel and now things are definitely a little clearer... But it didn't solve my problem, although it did improve the quality of my image. But I guess I want it to look as clear as the original and it sounds like that might not even be possible. So I tried all the different options and by far the best option seems to be using pngs instead of jpegs. So thanks for the suggestion R C-R! I also think the Lanczos 3 (non-separable) is the clearest, but the only problem is that it also darkens the line in my drawings... if it wasn't for that, this is what works best for me. Can anyone think of a way to resolve that problem? Since it's a drawing and my drawing is in a separate layer, I was wondering if making the line less dark before resampling would work? Something else to try...

In one of the articles there was a mention of using filters to sharpen a resampled image? Does anyone here know much about filters and how to use them?

What I was worried about with the DPI was the file size, that it would take longer to appear and would take up too much space. But in this case I'm more concerned with the quality.

v_kyr - I noticed there are no bicubic sharper option in Affinity, only bicubic. Are you saying bicubic sharper in Photoshop would be more effective? What is GraphicsConverter?

lenmerkel - The original image is 1926px by 2301px and I would like to resample it at 471px by 563px. Just to be clear, I'm not trying to print anything, I just wanted to reduce the pixel dimension.

[Guest]

I kind of concluded that my best option is just to increase my pixel dimensions, the image is never going to be clear at around 500px. I guess I have to give up having it displayed at exactly the dimensions that I would like it to be displayed.

Would it work better if the pixel dimensions of my original image were smaller?

[v_kyr]

11 hours ago, JosianeHoude said:

v_kyr - I noticed there are no bicubic sharper option in Affinity, only bicubic. Are you saying bicubic sharper in Photoshop would be more effective? What is GraphicsConverter?

You can probably yield similar results in AP with bicubic, when you apply some sharpening afterwards. - See GraphicConverter another imaging tool which offers much more options in this regard!

[Guest]

Thank you!

But what would Graphic Converter do that Affinity can't?

[Alfred]

On 02/12/2017 at 0:14 AM, Jhoude said:

I also think the Lanczos 3 (non-separable) is the clearest, but the only problem is that it also darkens the line in my drawings...

 

Did you try Lanczos 3 (separable)? I think you might find that it gives a more natural-looking result, not darkening the lines, although it probably won’t be quite as clear as the non-separable version.

[Guest]

I did, I tried all the different options. I think it was blurry... Using pngs and resizing the image a little less seems to work well.

Thanks!

[Guest]

Here's an interesting link that was recommended on understanding DPI, in case anyone here is interested.

http://sebastien-gabriel.com/designers-guide-to-dpi/