exr_use_alpha = GET_DEFAULT("EXR_USE_ALPHA", exr_use_alpha);
exr_compression = GET_DEFAULT("EXR_COMPRESSION", exr_compression);
tiff_cmodel = GET_DEFAULT("TIFF_CMODEL", tiff_cmodel);
exr_use_alpha = GET_DEFAULT("EXR_USE_ALPHA", exr_use_alpha);
exr_compression = GET_DEFAULT("EXR_COMPRESSION", exr_compression);
tiff_cmodel = GET_DEFAULT("TIFF_CMODEL", tiff_cmodel);