In general, you can't do well what you can't see well.
Many organ consoles are equipped with small lamps attached to or built into the music rest at the bottom of the rack; while these lights provide illumination, they tend to shadow, glare, and leave the top of the music score with insufficient light.
There are 2 ways to supplement any bottom mounted light:
You can have special overhead track lighting installed in the room which runs parallel with the bench and focuses the light on the keys and rack, or you can add a slim, low-profile music light (photo) that illuminates the entire height and width of the score evenly with no glare or shadow.
As many as 45 recessed LEDs in these types of music lights let you spread out and see multiple pages of music with uniform lighting and no highlights or dark spots.
These types of lamps have a brass light tube 30 inches wide supported by 2 brass legs attached to a hardwood base; they use little power, never get hot, and have a lifetime expectancy of some 50,000 hours of use.
In addition, similar types of lamps of special configuration, such as lamps with legs that permanently attach to the console fallboard or which mount on vertical organ cases often used in tracker organs, plus pedal lamps, coupler lamps, lamp dimmers, and controllers for multiple lamps can all be ordered on line these days to fill just about any organ lighting needs.