Diffraction Grating sheet 13,500 lines/inch - Double Axis 5ft Long x 6 inches Wide

I bought this purely for my elementary science class so we could make rainbow chocolate. (We've been discussing light, so this seemed like a great last-day-of-science treat.) It worked really well! I just melted the flat side of the Dove chocolates on a frying pan and then pressed the chocolates down firmly onto the sheet. It shows up best on dark chocolate, but you can see it on other kinds as well. (Sunlight shows off the rainbows best.) You can wash and reuse the film but you have to dry it (or you might get water residue that will mess up future chocolate rainbows). Also, be very careful not to crinkle it. The sheet comes in a cardboard tube, which I thought was great until someone threw it away, thinking it was trash. Big sad. If you buy it, put a label on the tube so that doesn't happen to you! The kids loved just looking through the sheet at each other and the windows, etc. Definitely a good investment!

I ordered this specifically for utilizing it on my 3d printer bed in order to give the first layer of my 3d prints a "rainbow" effect. I appreciate that Amazon had it at such a great value. The package arrived at a moderate pace but was packaged safely in bubble wrap packaging and comes rolled up in 5 individual sheets. Each sheet is long enough to cover 75-80% of my Creality V3 bed. It would require two sheets to fully cover the bed in entirety. In order to determine which side needs to be facing up, you can run a fingernail across the grating, if you can feel a slight ripple, you have the correct side up. If it is completely smooth, it is the non-grated side. You can also determine it by the reflecting light, if you see rainbows, then you are looking at the correct side (up). I applied this to my 3d printer's bed by laying down an initial layer of Elmer's gluestick, then rolled this on top of the glue, then used Frog Tape (slightly better than normal blue painters masking tape) all around the edges. You will want to ensure that there are no bubbles under the diffraction grating otherwise they will appear in the first layer of the print. You can re-use this over and over for quite some time as long as you don't wreck the diffraction grating sheet when removing the print. PLA and PETG stick quite well to the diffraction grating. I do not use any elmers on TOP of the diffraction grating (only under it to hold the sheet down). I really liked the effect this leaves on my 3d prints (see photo). Overall I would recommend this to others looking to do the same.

Husband love it

I purchased this diffraction grating to experiment with the kids at making holographic chocolate, and it worked perfectly! To make sure the grating is facing the correct direction, run your finger on a corner and listen for a squeaking noise. (For us, this side was facing toward the center of the roll.) 1. Heat dark or milk chocolate at about 50C/112F to melt. 2. Toss in a few hard chunk to seed the crystal structure. 3. Keep stirring until everything is melted. 4. Pour chocolate onto a baking sheet on which the diffraction grating is unrolled and facing upwards. 5. Place it in the freezer for about 10 minutes. (Any long will start collecting moisture.) 6. Pull out the sheet. 7. Flip the chocolate, and peel off the grating. Chocolate hologram!

See the photos I uploaded! I used this on my windows. This product creates amazing vivid rainbows across a room when mounted on a window and hit by direct sunlight. One thing to watch out for is that this product gets easily smudged with fingerprints. The smudges noticeably affect the diffraction. To prevent further smudges, I wore latex gloves while applying them on my window. Both sides diffract light the same so no worries as to which side you hold up to the light. This is slightly transparent; you won't be able to see clearly outside but you can make out shapes and objects pretty easily. From the outside in, you won't get much privacy, esp. at night. Day or night but more so in the daytime when it's sunny, the film reflects light away giving a opalescent effect to your windows. This certainly added a pizzaz to our home and is a conversation starter. It automatically puts people in better moods. Minus one star for how easily it smudges. I also wish they made this in bigger than 6" widths.

I've bought this product in the past and found the color intensity and separation to be excellent. This time the colors were softer and the separation of colors less distinct. Putting the old and new next to one another, the new product appears slightly cloudy while the old one is nearly perfectly clear.

Used this to make spectroscopes with my 8uth grade students. The film works very well and was just what I expected. Highly recommend this supplier.

Works in bright light. My son has loved rainbows since he was a baby. Now he is a tech expert so loved this unexpected cake top. I taped two sections of film together, melted chocolate over a double boiler and poured this over. Once cooled I pealed off the film and moved this to the top of a cheese cake. I heated a knife with a small torch and cut off the overlap. I used the waist to make stand up curls for the top. It turned out great, with fresh pitted cherries on the side. Fantastic.