Originally posted by Vendee My Phillips PCS150 enlarger is a tri colour design and I can dial in contrast adjustment without the use of filters which is great but if you want to make split grade prints, it means altering the setting on each of the lamps.
Luckily I have the option of using the "above lens" filter tray with Ilford sheet filters or use their below lens system. I'm thinking that, just like when taking photos, anything placed after the lens will degrade image quality to some extent and that the above lens filter is the best option. Am I right in thinking this or is it not that critical?
The holder below the lens is not intended for polycontrast/multigrade filters. It was designed for a safelight filter.
I agree with others that the ideal solution is just having a portable safelight near your dials and to use the enlarger as intended. Using the filter tray 'above the lens' is fine, but unless the dichroic filters are damaged or faded, not using the tri-lamp system is counter intuitive for paying for the cost and maintenance of three lamps instead of one but treating the enlarger as if it had a single light source.