Torelief WS 73 HX4 steel-backed polymer plates
Over a year ago, we began trying to find a comparable steel-backed polymer material that had the same desirable characteristics as the Jet plates, namely easy plate washout in water, lack of mottling defects in the slip coat and no weird chemical odor, which were all maddening problems in some other plates being sold. We investigated two other manufacturer’s offerings. One of them turned out to have consistency issues for use in intaglio printing. Thankfully, the other plate material turned out to be similar to the original LSL73SP plate we started selling 4 years ago.
Toray Torelief WS73-HX4 is the plate material we are now selling in addition to the Jet plate material. It has the same 0.73mm thickness as our original LSL73SP plate material. It washes out in water without any weird chemical smell, and is easily dried without frantically trying to prevent water drops from continuing to etch the plate. And we have seen no evidence of slip-coat mottling on these plates.
The Torelief WS73-HX4 material has a hardness of 65 Shore-D which is slightly less than our Jet LSL73 material had. We have seen no printing performance impact of this difference. For direct-to-plate techniques, we are using almost the same exposure time as we used for the Jet LSL73 material. The only downside is that it is slightly more expensive.
These plates have a green-colored surface when unexposed. As they are exposed and hardened, the polymer becomes a yellow-green color. We have been processing them the same way as the Jet plates: expose and then wash out in room temperature pH neutral water for 4 minutes. Dry with soft microfiber towels and then use a hair-dryer set on high for 3-5 minutes to remove all the water from the polymer. A second post-exposure hardening using the same time of the initial exposure (or exposures) will complete the plate in preparation for printing.
Treat these plates the same way as any other polymer material. Store them in a mylar bag to prevent them from drying out and curling in low-humidity environments.
These plates were easy to calibrate using our direct-to-plate calibration workflow. The exposure time was 2:30 for these plates compared to 3:30 for our LSL43-SM plates. We used a 2880-super resolution in QuadToneRIP to make our plates. A starter QTR profile for the Epson P800 is here.