White house washed in pink, green purple and torn skies

[AlyMac]

I have tried to resize this photo and it looks horrible. The white house is washed in pink, green and purple and the sky is torn. What am i doing wrong please?

[AlyMac]

sorry - im using a MAC and AP 1.6.7

Edited March 2, 2019 by AlyMac
forgot to add

[firstdefence]

Hi can we have some more details please, like what was the image size to start with and what have you resized it too?

What settings did you use to resize the image and could you upload the original file you started with  

[AlyMac]

Canon D5 - 17mm

File/export/ jpg/4368-2912/jpeg low quality/bi-linear/(slider to) 12

thanks in advance

Edited March 2, 2019 by AlyMac

[John Rostron]

1 hour ago, firstdefence said:

Hi can we have some more details please, like what was the image size to start with and what have you resized it too?

What settings did you use to resize the image and could you upload the original file you started with  

Your second version shows none of the artefacts of the first. However,  it would be useful to see the information that @firstdefence requested:

• What was the original size of the image (width by height in pixels)?
• What is the final size of the image (width by height in pixels)?
• Which algorithm did you use for re-sizing? (Was it nearest neighbour, Lanczos ...?)
• When you saved to jpeg, what quality did you use (the position on the slider)?

John

[v_kyr]

Try using RGB-16 bit for the image, don't compress too much and use a better resizing method like lanczos 3.

[AlyMac]

7 minutes ago, John Rostron said:

Your second version shows none of the artefacts of the first. However,  it would be useful to see the information that @firstdefence requested:

• What was the original size of the image (width by height in pixels)?
• What is the final size of the image (width by height in pixels)?
• Which algorithm did you use for re-sizing? (Was it nearest neighbour, Lanczos ...?)
• When you saved to jpeg, what quality did you use (the position on the slider)?

John

Hi John,

the original image was 24 MB - but Affinity shows the file to be 12..72 Mp 4368-2912

top of the screen I go to-

File

drop down menu Im clicking

"export"

clicking-

jpg

4368-2912

jpeg

low quality

bi-linear

I move the slider to the left to "12"

 

Just did it again and the white house is green and pink and the sky has dark waves through it

[emmrecs01]

Quote

jpeg

low quality

bi-linear

I move the slider to the left to "12"

I strongly suspect these are the settings which are causing the issue, especially "low quality", "bi-linear" and "12".  Try setting the quality to "high" or even "best", use one of the Lanczos 3 resampling options and the slider to at least 75 or 80.  (Personally I tend to use 100.)

HTH

Jeff

[John Rostron]

The artefacts you see are due to the low quality of the jpeg compression. Your image is not actually re-sized except in the sense that the overall file size is much smaller. (This means that the re-sizing algorithm is irrelevant.) You cannot have both a  highly compressed file and a good quality image. I suggest you experiment with the quality slider. Try to find a value that gives enough compression without the artefacts. Try round 75%.

John

[firstdefence]

Another question, why are you trying to compress the file so much?

[AlyMac]

2 hours ago, firstdefence said:

Another question, why are you trying to compress the file so much?

Hi - YES THAT  DID IT ! I was compressing the file too much - Many thanks - one and all 

Edited March 2, 2019 by AlyMac