Is there a maximum number of steps in the History Panel?

[Steve48]

If yes, where can user set it?

[Jeffrey Saldinger]

The number of history steps is set in Preferences>Performance, in the right-center of that panel. There is a slider that can be used to set the number; presumably the right-most position is the maximum. Mine is set to 100, which has been sufficient for my needs.

[Steve48]

Thanks for responding. Attached is a screenshot of my performance Preferences. I don't see the slider you are talking about.
I am using Lightroom Classic 9.3.- The latest version.

[Jeffrey Saldinger]

Steve, not having noticed that your question was posted under Lightroom, I answered the question as if it had been asked about Photoshop (where one can choose the number of history states to keep), not about Lightroom. My apologies for setting you on the wrong path to the answer. Perhaps there was something helpful (if off-topic!) in what I wrote.

[digitaldog]

Thanks for responding. Attached is a screenshot of my performance Preferences. I don't see the slider you are talking about.
I am using Lightroom Classic 9.3.- The latest version.

Because he's talking about Photoshop I believe?

There is no limit to history steps in Lightroom Classic.
You can clear some/all History but why would you?

[fdisilvestro]

As Andrew said, there is no limit, or should I say practical limit in the history steps in LR Classic. Actually Adobe has changed in recent versions the way it stores the history data in the catalogue (among other things) where now it is in bynary instead of text, which make it more efficient in space.
I would not worry about the history steps at all.

[Alan Klein]

I eat up a lot using LR "owned" V.6 spot removal and getting dust off of film scans.

I suppose you can clear the history section without clearing it by making a virtual copy after let's say the spot removals and start a new history for the virtual copy.  You still have the spotting history on the original file. 

You can also create a "snapshot".  But I've never used it and not too sure how it works.  Maybe someone can explain.

[fdisilvestro]

You can also create a "snapshot".  But I've never used it and not too sure how it works.  Maybe someone can explain.

Snapshots contain the same information as a history step but they are stored differently, and will be included in the sidecar files if you create them. You can use snapshots in ACR too, while history steps and virtual copies belong only in the LR Catalogue

[digitaldog]

Also think of a snapshot as a concatenation of multiple Histories. At least that's where they become handy.

[Alan Klein]

Can you illustrate a situation when you would use a snapshot?

[digitaldog]

https://helpx.adobe.com/camera-raw/using/camera-raw-settings.html

Save image states as snapshots

You can record the state of an image at any time by creating a snapshot. Snapshots are stored renditions of an image that contain the complete set of edits made up until the time the snapshot is created. By creating snapshots of an image at various times during the editing process, you can easily compare the effects of the adjustments you make. You can also return to an earlier state if you want to use it at another time. Another benefit of snapshots is that you can work from multiple versions of an image without having to duplicate the original.

Create and manage snapshots using the Snapshots tab of the Camera Raw dialog box.

Click the New Snapshot button  at the bottom of the Snapshots tab to create a snapshot.
Type a name in the New Snapshot dialog box and click OK.
The snapshot appears in the Snapshots tab list.

When working with snapshots, you can do any of the following:

To rename a snapshot, right-click (Windows) or Control-click (Mac OS) it and choose Rename.

Click a snapshot to change the current image settings to those of the selected snapshot. The image preview updates accordingly.

To update, or overwrite, an existing snapshot with the current image settings, right-click (Windows) or Control-click (Mac OS) the snapshot and choose Update With Current Settings.

To undo changes made to a snapshot, click Cancel.

Note: Use caution when clicking Cancel to undo snapshot changes. All image adjustments made during the current editing session are also lost.

To delete a snapshot, select it and click the Trash button  at the bottom of the tab. Or, right-click (Windows) or Control-click (Mac OS) the snapshot and choose Delete.

[Alan Klein]

Thanks Andrew.  That's a handy feature.

[rdonson]

You can also use snapshots in LrC as well. 

https://blogs.adobe.com/jkost/2019/09/working-with-snapshots-in-lightroom-classic.html

[Alan Klein]

Thanks Ron that was helpful. I usually make virtual copies.  That creates difficulty trying to track which is which .  Snapshots seem like a better way since you don't see or need to track multiple LR files to coordinate.  Just click on the Snapshot file you want within a single photo file.