Add reference to the rationale for not correcting alpha
diff --git a/transform.c b/transform.c
index 5fa5015..784cd28 100644
--- a/transform.c
+++ b/transform.c
@@ -655,6 +655,12 @@
}
}
+/* Alpha is not corrected.
+ A rationale for this is found in Alvy Ray's "Should Alpha Be Nonlinear If
+ RGB Is?" Tech Memo 17 (December 14, 1998).
+ See: ftp://ftp.alvyray.com/Acrobat/17_Nonln.pdf
+*/
+
static void qcms_transform_data_graya_out_lut(qcms_transform *transform, unsigned char *src, unsigned char *dest, size_t length)
{
int i;
