Hello all. I have been using the threshold effect in photoshop and found that it has decreased the resolution of the images when I go to print them (Print size - 3000 x 2700mm; Original Image size - 250 x 221 mm, 3456 x 3051 px at 350 ppi).
What is the best way to preserve image resolution using the threshold function, for the purpose of printing at large scale?
There is nothing in a threshold adjustment that can change the pixel size or ppi of an image, so if you are seeing that change, another step is responsible.
Please supply the following :
1. What version of Photoshop are you using (check in Help>System info)
2. What is the image size (in pixels) immediately before you use a threshold adjustment (check using Image >Image Size)
3. What is the image size (in pixels) immediately after you use a threshold adjustment (check using Image >Image Size)
4. Please show a screenshot of your print dialogue , ensuring scaling is off in that dialogue
Thank you for your response and apologies for my delay in getting back to you. Please find requested info below:
1. Adobe Photoshop Version: 22.2.0 20210202.r.183 2021/02/02
2. Image size 4608px x 3456px (before threshold)
3. Image size 4608px x 3456px (after threshold)
4. Please see attached image.
Thank you again for your help and please let me know if you need any more info.
Lines 2 and 3 in your reply give the answer. The size of the image is unchanged before and after the threshold adjustment.
Your print dialogue shows the correct physical size in cm for the pixel size converted at 350ppi.
So, I don't see any issues in the data you have provided.
" threshold effect" and "threshold function"
Can you explain further or post screenshot to ensure that we understand what are you doing in Photoshop. As @davescm stated above, there is treshold adjustment in Photoshop, are you reffering to that adjsutment or something else?
I never experienced change in image dimensions and resolution regardless of which filter/adjustment was used in the document. This part is not very clear: (Print size - 3000 x 2700mm; Original Image size - 250 x 221 mm, 3456 x 3051 px at 350 ppi) It appears your print size is 12X of original image? Photoshop on its own has lowered resolution to 30ppi or similar?
Simple fix is to visit Image > Image Size, uncheck Resample and change Resolution back to 350 or any other desired number.
You show the Threshold Dialog with the image's Luminosity histogram Where is the images its turning into pure Black and White no Grays? It is a very destructive change.