Two sheets of glass might both look gorgeous in a table, but handle very differently after you try to mark, cut and fit them in a small design. Some sheets of clear glass reveal all the tracing lines very easily. Some sheets of heavy textures look lovely but may be challenging to see patterns on. Some deep colors look great in the hand, but when it is away from the window looks a bit darker. Sheet glass choice is not just a matter of aesthetic, it is about how smoothly you can start learning.
The simpler sheets of glass will be easier to use for the early work. Smooth sheet glass sheets are easier to see the score line on, easier to follow a template on and easier to see if the cutter was consistent. Clear, lightly frosted and even-colored sheets may be more practical for first work, where you are learning how to gauge the amount of pressure on the score and control the snapping of the glass. Textured glass is not inherently bad, just more difficult, as the surface can alter both the feel of the cut and the visibility of the pattern.
One way to test sheets of glass is to hold the sample glass sheets over the same pattern paper and look at the tracing lines on it, then move the glass away and closer to the light. Check the visibility of the lines, the transparency of the colors, and the degree to which texture obscures detail. Such a test of lighting conditions prevents one from picking a glass sheet that looks great but makes the first project harder to work with than it needs to.
Consider the overall size of the project as you choose glass sheets. A first decorative panel full of very small glass pieces may prove to be very frustrating, even if it is a lovely set of materials. Small glass pieces offer fewer options for cutter position and scoring and snapping, not to mention smoothing. The larger, more simple pieces of glass provide more room to practice scoring a straight cut, check the fit of a piece and clean it off and smooth the edges for the final assembly. The first few projects ought to let the hands learn the job, not test the limits of all the skills at the same time.
One should look carefully at color as well. Transparent glass, for example, will let a good deal of light through and the transparency changes during the day. Opaque glass is more like a solid block of color, which may or may not be helpful when trying to see a pattern or drawing on the surface. Frosted surfaces soften the design. Clear glass shows off all the edges and any debris on the glass, as well. Clean the sample glass before the final decision and view it from various angles. Dust, fingerprints and smears from cleaners are visible from the different directions and may change the glass sheet’s look.
The first choice of a glass sheet should be one that makes for better practice, not one that makes a show of the results. Choose glass that allows you to easily see a pattern, score it precisely, snap it neatly and smooth it smoothly. With the right glass, each step is easier to see: the scoring, the breaking, the fitting, the smoothing and how light affects the finished piece.