If you're one of the millions of people who enjoy watching James Garner and Mariette Hartley inter-relate on those cleverly written and well-produced commercials for Polaroid's Time-Zero cameras and film, you'll be disappointed to learn that the duo has been replaced beginning this fall.

Ahh, but shed no tears, for Garner and Hartley will be back on the tube, this time promoting Polaroid's new 600 Sun cameras and 600 ASA film. But who will take their place pitching the Time-Zero products?

According to Polaroid's Pamela Wright, the new Time-Zero spokesmen will be none other than the Muppets. Keep your eyes open for Kermit the Frog and Miss Piggy, along with a host of other Muppets characters.

If you use Iiford's Cibachrome color print material in producing your own prints from slides, get ready for some good news. The Ciba-Geigy firm recently announced it has begun a two-month manufacturer's rebate program, good through September 30, 1981. Anyone buying either a 20-sheet package of 8x10-inch Ciba-chrome-A or a 10-sheet package of 11 x 14-inch material is eligible to receive a $5 rebate. Purchasers of 50-sheet packages of 8x10-inch Ciba-chrome-A or 20-sheet packages of 11x14-inch material may receive a $10 rebate. The rules require that the retail buyer mail to the Ilford Rebate Center a dated sales or cash register receipt and a brief verification form signed by the dealer. The offer is limited to one rebate perhousehold and is valid only in the U.S. where not prohibited, taxed, or otherwise restricted by law. Check with your photo dealer for more information.

If you're into making home movies, you should check out three new and improved super 8 Kodak Ektachrome 160 movie films, which feature improved sharpness and finer grain, according to Eastman Kodak Co. The films include 160 movie film (type A) in 50-foot silent cartridges; 160 sound film (type A); and 160 silent film (type G) -- all Ektachrome. The films, which feature "new improved emulsion characteristics," will use a new process (EM-26) and will be available in late summer. List prices will be the same as for the films they replace.