Three Image Overlay Apps. Do More with Your Reference Images While You Work

PureRef's image overlay in action
with Cartoon Animator 4.

One thing Cartoon Animator 4 still does not have in stage mode is the ability to onion skin previous and next frames. 

For those complete animation newbies among you, onion skinning is the ability to see through the current frame to your previous and/or next keyframes so you can see the progression of your character or object's movement as you create and adjust each keyframe. Usually the previous and next frames appear lighter so your current frame remains the key focus.

This prompted me to look for a tool that could overlay an image over my work to use as a reference while still allowing me to work on the app underneath the overlay. I had seen, and even used such apps in the past but it had been some time so I decided to see what was out there, preferably free and/or open source, with versions for Mac and Windows.

Overlay 2

There are actually a number of apps that do nothing more than overlay an image but the only one I could find that has both Windows and Mac versions is Overlay 2.

You can trial Overlay 2 for free but it will constantly display a nag screen every 3-5 minutes asking you to enter or obtain an activation serial number. To purchase a license it'll set you back US$25.00 - worth it? Let's see.

Overlay 2 with Cartoon Animator 4.

Overlay 2 does exactly what you expect. It allows you to overlay an image on your screen, at any percentage opacity you require. You can then set the image to 'float' which means you can work on any app underneath as if the overlay image wasn't there.

Additional controls allow you to scale, rotate, or move the image vertically and horizontally, as well as turn the overlay on or off.

I can't really fault the app. It does exactly what it says it does and works well. I just don't feel it's enough to justify $25.00 for a license.

One feature it could use is the ability to switch through a sequence of images stored in the same folder at the push of a button the way most photo viewer apps do. This would allow you to easily change to a different reference image without having to manually load in each image every time.

If all you need is the ability to overlay one image, that you can work through as if it wasn't there, on any app, not just Cartoon Animator 4, this will do the job.

Kuadro

Kuadro is completely free, with Mac and Windows versions, is more than just a reference image overlay tool. It's also something of a visualization board for your monitor allowing multiple images on screen, all in their own windows. You can save the layout of those images to reload later. You can also automatically add images saved to the clipboard (which means I can screenshot my previous keyframes to the clipboard and use it immediately as an overlay reference for my next keyframe).

Kuadro allows you to zoom and pan around images within their windows, set their opacity, and whether they always remain on top or not when you switch back to your other apps. Locking images so they can be worked through as an overlay can only be done for all images at once. So once locked you can't move any images around until you unlock them.

Kuadro with Cartoon Animator 4.

Kuadro does allow you to flick through a sequence of images in the same folder just by pressing the left and right arrow keys when an image is active (though I did encounter a bug where my images got progressively smaller each time I flicked through them). 

If you're considering this app, it definitely fits better into your workflow if you take the time to learn the keyboard shortcuts. Otherwise you'll constantly be selecting things through the app's menus. Adjusting opacity is definitely easier using the short cuts as there is no slider or numeric setting within the menus to fine tune how opaque you want to go.

One important thing to note is that Kuadro doesn't actually install to your system (on a Windows system it won't make a shortcut in the start menu or on the desktop). You'll have to make your own shortcut to wherever you downloaded the Kuadro executable file.

PureRef

PureRef - is like Kuadro but with even more features. Again it's totally free and available for Windows, Mac, and Linux.

It can do pretty much everything Kuadro does, though you can't flick through images in a folder. Work spaces are organised into canvases in which you can store multiple images on a single canvas (which is basically a window). A canvas can be overlayed and/or locked.

A nice feature is the ability to attach text notes to images.

PureRef with Cartoon Animator 4.

As near as I can tell PureRef has a few extra features over Kuadro and is, perhaps, a little more finished and professional. I certainly didn't encounter any bugs. Some how Kuadro managed to feel a little more light weight and less intrusive on my screen though.

Both do the job of organising visual references on your screen while you work in another app really well. Since both apps are free it really comes down to which you prefer and whether attaching notes to your reference images is something you really need.

Either makes the US$25.00 license for Overlay 2 redundant since both surpass that app in features for no cost at all.

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For my purposes of just overlaying reference images I think Kuadro is more than enough. If they fixed the issue I had with flicking through a folder of images it would be perfect. Since both apps work better if you familiarize yourself with their shortcut keys, Kuadro has fewer of these to learn.

Overall I think PureRef is the better app feature for feature with the concept of canvases giving the edge in terms of feeling more organised but you really can't go wrong with either. Give Overlay 2 a miss unless it becomes freeware or someone decides Kuadro and PureRef should be paid apps.