The edit histories don't appear to be "exactly" the same to me. Are you using the same process version in both instances? Are all settings exactly the same in both instances?
as you can see the edit histories are both set to the same point, but beyond that point they've taken different pathways.
that being said yes, the process versions are different as obviously LR 2015 and LRC 10 have different default processors, but other than that everything is the same as all I've done is upgrade the catalogue. Also when I change the processes in LRC 10 it doesn't fix the problem.
There's also the change in camera profiles post-2015. That was the switch from Adobe Standard to Adobe Color as default profile.
Similarly, new process versions contribute to expected differences.
2015 and LRC 10 both use adobe standard as default and using processing versions 3 and 4 as opposed to version 5 in LRC 10 doesn't help
I did notice at one point in the past, when new choices and kinds of profile arrived in LrC (such as Adobe Color), images' profile got 'silently' switched when it was Adobe Standard (my usual default), to Adobe Color - even though I didn't ask for that to happen. Actively returning the image to Adobe Standard (if that was what I used before) while retaining the same process version and adjustments as before, has (for me) produced the same visual results as before. But that was an action I had to do.
That said, it has always been the case that the profiles for a given camera model may be altered in a Lightroom (Classic) version update. Usually in response to customer complaint that this profile is not delivering what's wanted. Since (e.g.) Adobe Standard is not a single profile, but a whole bunch of different Adobe Standard profiles, each one specific to a camera model - only images using a changed per-camera profile will see any difference. So different people have different experiences with this version update. A profile underlies all adjustments so change is seen even when the process version and the adjustments remain identical. Typically this is some subtle detail, or colour-response improvement but sometimes there is more of an obvious wholesale tone / colour change seen. As much as, when switching between Adobe Standard ('basic vanilla') and Adobe Color ('sweetened vanilla').
yh I'm kind of expecting that photos are just being dealth with differently but wodnering if there's anything I can do about it as it's making LRC unusuable for me as there are other issues I'm tyring to work around
What is the "1" history step right above the Import Step. I have never seen a history step like that.
it's the name of my preset
I see a couple issues.
1 When you apply a preset it shoud say Preset:1 not just 1
2 There is no longer a "Enable Split Toning" item. Its called "Enable Color Grading". Maybe there is an issue with upgrading from Split Tone to Color Grading but that would have showed up in the forums a long time ago.
Click the history step one below Enable Split Toning to see what happens.
Also, if you click the Import Step in both version do the photos look the same?
they don't look different on the import step but the exact same picture with no presets look different in the different versions of illustrato, and if you export them out they both look different, so I guess it's something I've got to live with
I already have other images that I've exported with the grading on go grainy, doesn't make a difference