Baryta budget alternative

Started 3 months ago | Discussions thread
Mark McCormick Senior Member • Posts: 1,534
Re: Baryta budget alternative
2

al404 wrote:

On their website it says "Manufactured exclusively from cellulose fibres" as far as I know only cotton based parer are OBA free

Optical brighteners can be and are added during the paper manufacturing step to either wood pulp papers or cotton papers. Hence, any base sheet can have or not have OBAs. But neither traditional wet process photo nor inkjet paper manufacturing stops at the paper base manufacturing step. Coatings are now added, indeed multiple coating layers in some of today's best inkjet media. OBAs can and indeed typically do get added into some of those coating layers. Both the amount and location of OBAs in the various coating layers along with the amount of UV energy reaching the print surface while on display determine how much fluorescence the final media product will exhibit. The visual effect on display is quite variable.

Simply put, OBAs make whites appear to be "whiter" which is why they are so popular. Virtually every popular laundry detergent on the market today has OBAs to make your clothing look brighter and thus perceived by the consumer to be cleaner. The paper and coating industries apply the same logic which is why so many photo papers contain OBAs.

But make no mistake. OBAS always reduce the "archival" properties of the media because they are fugitive dyes, especially when added to microporous coatings, so printing with a pigmented inkjet printer on an OBA containing paper creates a "hybrid dye-pigment" print   Folks can rationalize print permanence in many different ways. And prints can be cared for in many different ways. The more one understands how the media behaves in real world environments, the more opportunity there is to care for the print wisely and get it to last a long time.

Easiest way to determine OBAs and even to some degree the magnitude of the optical effect which may get compromised when UV blocking glazings are used is to shine a UV LED flashlight on the print surface. Lots of OBAs....Lots of "bright blue glow" from the flashlight. Place a UV blocking glazing over the paper...little or no "blue glow".

Note: LEDs intended for indoor lighting have almost no UV content. UV LEDs are specially formulated to emit UV radiation, the peak is typically 365 or 395nm. The 365nm variety is better for detecting the paper fluorescence, but both wavelength UV LEDs will get the paper to fluoresce noticeably when OBAs are present.

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