Scale or Crop?

[MikWar]

When working in the Develop Persona, I would like the image of a distant bird to fill the screen.  I have always used Crop in Apple Photos to accomplish this.  In AP, what would be the difference between Scale or Crop to accomplish this?

[MEB]

Hi MikWar,

Welcome to Affinity Forums :)
In Affinity Photo crop will do the same as Apple Photos, that is, get rid of the parts of the image you are not interested in, keeping just the cropped area as the resulting image.

Scale, scales the whole image up or down as a whole. While a crop changes the composition of the image removing elements/parts of it thus re-framing the main subject, scale preserves the original composition intact - just adds or removes pixels proportionally to the image width and height dimensions (assuming you have both dimensions linked).

So if you want to get rid of part of the sky or the surroundings and just re-frame the bird without altering the original bird pixel data, a crop will do what you want. If the bird has not enough detail because it was too fat when you took the picture scaling the image up may help but it will deteriorate its quality a little since you have to increase/add more pixels to the cropped area artificially (adulterating the original pixel data).

[toltec]

Crop just throws away information, in theory, because Affinity keeps it in case you want to undo the crop. 

 

Scale will attempt to increase the image resolution by resampling. Basically, adding more pixels where it thinks they should be. Which sometimes works very well, sometimes not, depending on the subject and the method you use. I don't know what method "scale" in  Develop uses, probably Bicubic, which is OK but basic.

 

If you want your bird to fill a larger area (zoom in) it will probably end up looking a bit blurred or pixelated. So, I would experiment with resampling methods, not just use the basic method.

 

Making a picture larger is quite an art, because the software has to add detail intelligently. There are choices of resampling methods (different algorithms) and choosing the best one for each type of image can make a BIG difference. Do this in the Photo Persona Document > Resize Document. Start at bicubic then compare it with Lanczos or Lanczos 3. Each works better with different subjects but Lanczos methods do take longer. Methods like Bilinear and Nearest are for resizing down only.

 

 

To speed thing up with Lanczos resampling, crop first, make Affinity discard the cropped bits by going Layer > Rasterize. Then when you increase the size, it only has to work on the cropped bit, which will be faster.

 

The other option is to go back and ask the bird to come closer ;)

 

Please let us know which works best!

 

[MikWar]

1 hour ago, MEB said:

Hi MikWar,

Welcome to Affinity Forums :)
In Affinity Photo crop will do the same as Apple Photos, that is, get rid of the parts of the image you are not interested in, keeping just the cropped area as the resulting image.

Scale, scales the whole image up or down as a whole. While a crop changes the composition of the image removing elements/parts of it thus re-framing the main subject, scale preserves the original composition intact - just adds or removes pixels proportionally to the image width and height dimensions (assuming you have both dimensions linked).

So if you want to get rid of part of the sky or the surroundings and just re-frame the bird without altering the original bird pixel data, a crop will do what you want. If the bird has not enough detail because it was too fat when you took the picture scaling the image up may help but it will deteriorate its quality a little since you have to increase/add more pixels to the cropped area artificially (adulterating the original pixel data).

 

Thanks for the clarification.  Is it fair to say that when you Crop, and then the cropped image becomes as large as the original image, that the computer automatically Scales the image after cropping?

 

[MikWar]

1 hour ago, toltec said:

Crop just throws away information, in theory, because Affinity keeps it in case you want to undo the crop. 

 

Scale will attempt to increase the image resolution by resampling. Basically, adding more pixels where it thinks they should be. Which sometimes works very well, sometimes not, depending on the subject and the method you use. I don't know what method "scale" in  Develop uses, probably Bicubic, which is OK but basic.

 

If you want your bird to fill a larger area (zoom in) it will probably end up looking a bit blurred or pixelated. So, I would experiment with resampling methods, not just use the basic method.

 

Making a picture larger is quite an art, because the software has to add detail intelligently. There are choices of resampling methods (different algorithms) and choosing the best one for each type of image can make a BIG difference. Do this in the Photo Persona Document > Resize Document. Start at bicubic then compare it with Lanczos or Lanczos 3. Each works better with different subjects but Lanczos methods do take longer. Methods like Bilinear and Nearest are for resizing down only.

 

 

To speed thing up with Lanczos resampling, crop first, make Affinity discard the cropped bits by going Layer > Rasterize. Then when you increase the size, it only has to work on the cropped bit, which will be faster.

 

The other option is to go back and ask the bird to come closer ;)

 

Please let us know which works best!

 

 

Thank you for the very detailed information.  I will try several methods and let you know!

 

[MEB]

18 minutes ago, MikWar said:

 

Thanks for the clarification.  Is it fair to say that when you Crop, and then the cropped image becomes as large as the original image, that the computer automatically Scales the image after cropping?

 

Hi MikWar,

No, that's not correct. In Affinity Photo after you crop the image Affinity Photo will zoom it so it will fill the screen area but this doesn't mean the image was scaled up. It only means the image was zoomed  in (that is rendered in a closer view) to fill the screen area. You can do the same with the Zoom Tool (the loupe icon on the left toolbar).

Don't confuse zooming (in or out) with scaling (up or down). Zooming only shows the image closer or farther on screen. It doesn't actually change the image size/dimensions, while scaling does change the image dimensions.