2010/7/12 Laurence Cuffe <cuffe@xxxxxxx>: > > What about a Pola-Screen? I can not find a > reference to polarization in the IB for my camera. > > Marc > > Yes good point. Thats another glaring exception to the notion that it can > all be done in Photoshop. Regarding a polarizing filter for PS and others image edition software, it's necessary to distinguish two main practical effects you can obtain from a regular true polarizing filter used during the image taking. The effect to obtain deeper and darker blues for the sky and for the greens, etc. can be obtained using PS or similar software judging the image after to take it, you don't need a Pola-Screen for this case. It can be done working with the R-G-B channels in PS or it can be easily done with simpler tools like the Sky graduated filter from Picasa. This is a method for PS: http://photoshoptutorials.ws/photoshop-tutorials/photo-effects/polarizing-filter.html However there is another very useful effect you can obtain from a true Pola filter (Rolleipol f.e.) that cannot be obtained from PS and similars; this is the effect to eliminate reflections from bright and transparent surfaces allowing to capture subjects beyond this surface, f.e you wan to capture fishes and stones within clean and transparent water but the reflections are avoiding to see them, turning the Polafilter you'll find a point where the light is polarized and the reflections are eliminated allowing to capture fishes and stones. If you want to capture the _real_ image for this and similar cases, you need to use the filter during the image taking, PS cannot invent the real subject. Carlos --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list