Digital BW, The Print

On 11/03/2013 06:58 PM, pdesmidt tds.net wrote:
> If I understand correctly, OBAs turn UV light into bluish visible light,
> which causes paper with them in to look brighter when exposed to UV
> light.  Substances that make the paper whiter by making it reflect more
> white visible light, such as baryta or titanium dioxide, don't do the uv
> trick.  The problem with OBAs, other than a slight blue shift, is that
> they'll eventually stop performing their trick, which'll cause the paper
> to appear yellower.

Actually TiO2 does the UV trick but we can not see it. It absorbs UV 
light as well but emits the energy as heat beyond the red wavelengths. 
OBAs tend to perform better with Barite than with TiO2 as there is no 
competition in the absorption of UV light with Barite..

-- 
Met vriendelijke groet, Ernst Dinkla

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2012: 500+ inkjet media paper white spectral plots.