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 microporous and cast coated photo papers.
Microporous photo papers:
This type of photo paper is almost always made with the top quality, PE Coated base paper (see previous post). The main benefit of this base paper is enhanced stability of the final product.
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.
Microporous 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.
Microporous paper normally comes in 3 finishes:
- Gloss finish – Has different levels of gloss and can be measured and scored for glossiness.
- Satin finish – also known as semi gloss, has lower glare and provide the benefit of non reflective surface.
- Pearl finish – a satin finish with a higher gloss and benefit of providing vibrant deep colours, but yet still has a lower reflection/glare than the gloss paper. This paper is often used by the professional market from photographers to graphic designers and printers.
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.
The professional grade, more superior product is clearly the microporous range of papers. The cast coated ranges are normally cheaper and provide satisfactory results for a wide range of needs.
If your photos are displayed in exhibitions or are viewed by discerning clientele, use the microporous range. Whether you use Gloss, Satin or Pearl depends on your taste and the required end result. Remember that you can not print on the reverse of most microporous papers although they can be written on with a pen or a felt tip.
The cast coated papers on the other hand can be printed on the reverse as there is no coating there and the ink will be absorbed.