Why not use this method of hiding text messages. Revealed with red glasses.
For an example use the red lens of a pair of 3-D glasses for an instant reveal in the sample message shown here.
We stock red reveal cardboard glasses in various styles and sizes: hand held or with arms, even Spy Glass. Why not have them custom printed to your own design with any message or logo, or even cut to a custom shape.
For graphics see our Focal Decoder™
For 3D Magic, try Magic Eye™
Please contact us for a quotation or further details.