The file extension ACV marks so-called Adobe Photoshop Color Curves files, ie color-curve files of the image-editing software Photoshop. Color curves, for example, can be used to change color values such as red, green, blue or tonal values for highlights and shadows in an image.
In the German version these files are called gradation curves.
The dialog box can be reached under 'Image-> Adjustments-> Gradation curves'. In this box curves can be saved and loaded. Usually ACV files are stored under Preferences / Curves. This makes it easy to reuse useful settings.
Most often resolving problems with opening ACV files is very simple. Just install an appropriate program that supports such files. All of the listed programs support ACV files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of ACV files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate ACV files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the Adobe Photoshop applications is not on the list, select "Browse" option in order to manually locate the directory where Adobe Photoshop has been installed.
Sometimes problems with opening ACV files may not lie with the application itself, but can arise due to other causes, such as: