When I edit my ARW file with Sony's Image Data Converter and reopen the file in Photoshop, I don't see any differences in there. Why is this? Can I give Photoshop the modified version losslessly somehow?

(e.g. Is there perhaps to store the IDC changes in an XMP file that I can use in Photoshop?)

  • \$\begingroup\$ The .ARW file is a proprietory Sony file format to contain the Sensors RAW File. This uncompressed image data can be manipulated in the Sony Image viewer, but needs to be exported to a format for the adjustments to be saved. formats to consider could be TIFF. these will then open in Photoshop with the adjustments showing \$\endgroup\$ Aug 9, 2015 at 23:11
  • \$\begingroup\$ @AbdulNQuraishi: Thanks. Should I use 16-bit or 8-bit TIFF? And I assume the TIFF conversion is lossless? \$\endgroup\$
    – user541686
    Aug 9, 2015 at 23:42
  • \$\begingroup\$ TIFF is uncompressed and Lossless. You may find that after exporting, the image size may actually increase. The sony Software may allow you to export with the changes in .PNG also and this is also a Lossless format but a lot smaller in size. it also seems to be format of choice for Adobe. 8 Bit colour Depth is good if you are experimenting, but with 16Bit Available, when it comes to serious work, it cannot be ignored. Try them both, you may not initially see that much of a difference \$\endgroup\$ Aug 9, 2015 at 23:52
  • \$\begingroup\$ TIFF is only lossless with what you choose to include in the TIFF. If you raise the black point or lower the white point, everything outside those limits is lost when converting to TIFF. CT/WB is also "baked in", though with 16-bit there's still much more room to make minor shifts than with 8-bit. \$\endgroup\$
    – Michael C
    Mar 10, 2023 at 10:31

1 Answer 1


This is how lossless editing works. This is a BIG concept. Lossless edits never change the original data, edit versions merely store the list of edit operations we specify. If we subsequently edit the data more times later, we never change the original data, we merely edit the list of changes. Then we "output" the change by writing a new JPG file copy, only then the changes are applied, only in the copy. The original data is always kept 100% intact. Other programs, like Adobe, do not know how to apply the list of proprietary changes made by like Sony, same as Sony does not know how to see Adobe changes. Other programs don't understand, so they only see the original data, and necessarily ignore any change list. We write the JPG copy so other programs can see our changes. Lossless editing.

Same way with losslessly editing JPG files, other JPG programs don't understand how to do our methods, and they can only see first JPG original. Lossless edits always have to output new JPG copies so other programs can see it.

The goal is NOT to to be proprietary, but is to be lossless. Any output has to know how to apply the list of changes to a copy of the original data, to output a new JPG copy with changes.

The original remains our stored archived master copy. Subsequent edits do NOT have to suffer undoing previous data shifts, but instead any and every output always begins with the pristine original master and the Current list of edit operations. Edit shifts are done only ONE time, and there is only ONE added set of new JPG artifacts. When we want additional editing in the future, we DISCARD that first expendable JPG output copy, and we edit our list of changes, and then we OUTPUT a new JPG copy for whatever other purposes, which replaces the first expendable JPG copy. Lossless editing.

  • \$\begingroup\$ Good explanation for those who don't already understand the idea of lossless editing, but I already do. My question was about how to make changes in one program that are reflected in the other program, which need not be lossy. \$\endgroup\$
    – user541686
    Aug 10, 2015 at 0:19
  • \$\begingroup\$ Both programs might read the original camera raw file format, but they cannot read each others edit list format. They are different editors, with different styles. So if you want a second program (which could not care less how the first program works) to see the first programs edit change, the way to do that is for the first program to output a new JPG or TIF file for the second program to see. Or to simply start over in the second program. \$\endgroup\$
    – WayneF
    Aug 10, 2015 at 3:18

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