Curves have no points in imported Photoshop files

[Becka]

Hello, I have some old TIFF files saved by Photoshop CS5 or 6 which contain curves.  When I load these files into Affinity Photo all the layers are present, however curve ones are just a straight line, the points seem to have not been read.  I could not see anyone else with the same problem when searching the forum, so presumably they should have been imported correctly.  Is there a special way I need to import them, or is it an issue with them being TIFF files rather than PSD?

I am using Affinity 1.10.5 on macOS 10.14.6 

[firstdefence]

Hi @Becka Do you have an old TIFF file you can upload?

[Becka]

Yes, of course.  Here is one which had been resized for making a copy for the web (so not a huge upload now) but has not been touched since 2014.  It has a slight curve for contrast but is just an "empty" curve layer when loaded in Affinity Photo.

IMG_1113210.tif

[R C-R]

11 hours ago, Becka said:

When I load these files into Affinity Photo all the layers are present, however curve ones are just a straight line, the points seem to have not been read.  

When I open your IMG tif file, it has no curve layers but it does have two adjustment layers, only one of which is a Curves Adjustment. That adjustment has just a flat curve, so it has no effect on the image. Is that what you mean by "just a straight line"?

[Becka]

Yes, sorry if I am not using the correct terminology but that is what I mean.  It is an unadjusted line with no curvature when there should be three points along it.  It seems to me that Affinity Photo is reading the presence of a curve layer, but not the data for it.

This should have occurred to me earlier but I still have CS6 installed on my old computer, so I have attached a screenshot of what the curve should look like.

[joe_l]

5 hours ago, Becka said:

seems to me that Affinity Photo is reading the presence of a curve layer, but not the data for it.

This seems to be a limitation of how AP reads the TIF. Save it as PSD and the curve is preserved.

[Lee D]

The TIF standard by default doesn't support layers, however apps like PS and Affinity Photo can export to a Tif file with layers but the layer data/information is kept in a separate TIF tag which is then read by the app opening the file (if supported). However the method of how this data is written/read may vary, especially if from an older app to begin with, which may be the case with CS6, this isn't the case if exporting out as PSD.

[Becka]

Thank you for the explanation Lee, and to everyone else for their help.  The irony is the files were originally saved as TIFF to be more future proof than using a proprietary format!

As it does not seem to have affected anyone else I know Serif will not even bother to consider whether it is worth their time to make Affinity Photo compatible with this format.  So I suppose the question is now, does anyone know of a good free convertor for Photoshop TIFF files to PSD?

Needing to have a copy of Photoshop just for this task would be a rather expensive solution