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CedarHouse

Resize Document

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I have touched in this before but came back to the 1.7.2.414(Beta) on Windows 10 PC to see whether the action was the same as the full 1.7 version. Loaded an image at 4500px by 3000px (15in by 10in) at DPI 300.  Menu item Document and then Resize Document. Change DPI to 200 and untick the resample box. (Only changing the DPI value). Image is 4500px by 3000px (22.5in by 15in) which is correct as lowering the DPI should increase the image size but keep the pixel size constant. Click on the Resize button. Menu Bar to the top left pixels change from 4500px by 3000px to 3000px by 2000px, when it should remain at the constant value of 4500px by 3000px. Re-open the Resize Document and the image size is still 15in by 10in at a DPI of 200, but the pixel size is now 3000px by 2000px. This would give the 15in by 10in at DPI of 200 but image dimension should really be 22.5in by 15in. Sometimes when clicking off the tick in the resample box the image size does not change at all.

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Maybe I am being to quick in response to the recent beta version 424. Still cannot see any change with regard to the Document Resize and DPI settings relating to the resolution and size or area of an image. I have taken onboard an example from a Digital Photography book from 2005. Imagine a 2D Universe that is expanding. Initialy there are lots of stars occupying a small area of space. As the universe expands the area that contains the stars get bigger and bigger. The quantity of stars remains the same as the area of the universe increases. The way to describe the change of size of the universe as it expands is to determine a resolution. So one can determine a value for how many stars there are in a unit of length. Called the Resolution. More stars per unit length will occupy a smaller area and fewer stars will occupy a larger area. Same with pixels in an original image from the camera. The pixels should stay the same but as the resolution changes then the area of the image will increase or decrease. The original pixels have no size, just a quantity of pixels. The size is determined via a resolution of some degree of measurement. i.e 300 pixels per inch (ppi of DPI) or 100 pixels per inch (ppi of DPI) or maybe 50 pixels per inch (ppi of DPI).

Digital Images.pdf

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Further consideration is with the Photo Personae and the document sizing. I can figure that the current method is to re-sample the image when changing the DPI and yet retaining the original or cropped size by changing the pixel quantities. But I do not need to do this operation in the Photo Personae. All I want is to edit the image from a digital camera and then do the re-sizing or resampling at Export. I use an RGB monitor that claims about 97% of the Adobe RGB (1998) colour space and have set this colour space in preferences and in the Develop Personae as Adobe RGB colour space for all editing. I could use the ROMM RGB (ProPhoto) colour space if I require to do so. Printing images in these colour spaces direct from the Photo Personae is not an option as I am in a larger colour space and the prints come out with the wrong shades and with colour shifts. When exporting the image is then re-sized if required and then set to the SRGB colour space and saved at the appropriate size and this is what I use to print and the colours and tones are excellent and using a fully calibrated monitor the screen colours very nearly match the print colours. Still will be a slight difference as the monitor is backlit and prints are reflected light and have to viewed under daylight for any real comparison.

In the Photo Personae all that is required is to be able to choose the appropriate ppi (DPI) to resize the image. Edit the size in the CROP tool to an absolute size (a specific dimension) move the crop grid around the image for effect. (Rule of thirds etc) and crop away the pixels I do not require to be part of the new image. Can then rasterize if I wish and if I have no intention of returning to the original pre-crop size. Then export the image at say 8 bit and SRGB colour space at a specific size for the type of image I want to print or use elsewhere. It is only at Export that I need to resize or resample an edited image. I want to retain all the image/pixels or edited image/pixel sizes in the .afphoto file format in case I come back to either re-print via export or revise my edits and then export. 

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When Resample is inactive, it must never change the number of pixels. If the user changes the DPI, mm must be calculated automatically (from constant pixels and dpi). If the user changes mm, the DPI must be calculated automatically (from constant pixels and mm).

Correct image resizing is must working as in this video:

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Version 1.7.2.424 (Beta) Affinity Photo for Windows.

Not wishing to say anymore on this as Affinity Photo is not performing for printing and sizing images. It takes time to check through the Document Resize and Cropping options, but can not see any consistency in the approach. Attaching files for differing crop modes. See second set Images A to C and observe the changes in the top bar at different DPI values. Compare the inches values to the pixel values at the different DPI values.

One should read a tutorial from [photoshopessentials.com] Home> Photoshop Basics Chapter 05 Lesson 01 Pixels, Image Size and Image Resolution in photoshop. Lessons 03 and 05 are worth a good read. Essential reading.

Image1_Initial_image.jpg

Image2_Unconstrained.jpg

Image3_Absolute Size.jpg

Image4_Back_to_Unconstrained.jpg

ImageA_Absolute_Size_crop.jpg

ImageB_AbsoluteSizeInches.jpg

ImageD_DPI25.jpg

ImageD_DPI240.jpg

ImageC_Absolute_Size_DPI96.jpg

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