posted on 2017-05-08 15:52:48
Photo papers are a very general term applied to a wide range of high resolution coated inkjet papers. The most popular types and the subject of this article are the resin coated and cast coated photo papers .
Resin coated photo papers:
The microporous layer is the superior coating used for inkjet photo papers. The coating has micro pores or nano pores (smaller pores than micro) which are silica or alumina based (rare these days due to high cost). What is important to note is that this coating, due to its pores, can accommodate all type of inks; dye and pigment (see previous post for info) and can cope very well with the particles in the pigment inks which “sit” well in or on the pores of the microporous coating.
RC paper is normally instant dry and water resistant. The microporous coating will provide a better colour definition with a deeper, more solid black than the cast coated paper. Quality of course, varies between different manufacturers and some will provide better quality imaging than the others.
Cast coated photo papers:
The cast coated paper comes only in gloss finish due to its specific production method. This photo paper is based on normal paper, unlike the microporous that is PE based.
In the coating process, the paper goes through hot metal rollers after the coating has been applied.The rollers press and heat the coating which causes the paper to become glossy with a flat surface. Due to this method of coating there are no pores on the face of the paper and pigment inks can only “sit” on the surface. On many occasions this causes ink on a freshly printed paper to smear when rubbed.
There are higher quality cast coated photo papers which are referred to as super cast or super pore that use some of the microporous technologies and contain some chemicals which cause the pigment ink to adhere to the paper better and prevent smearing.
The cast coated photo paper is excellent for dye based inks and has a lower quality results with pigment inks. Some ink manufacturers started adding adhesives to their pigment inks to make it compatible with cast coated papers and prevent smearing.