With an incandescent bulb, the Watt rating simply indicates the amount of ELECTRICITY USED, and NOTHING to do with the amount of Light output by the bulb!!!
When substituting an LED, the amount of electricity consumed is about 1/10 what an incandescent bulb would use, and about the same amount of light would be output by the LED. An incancescent bulb of one Wattage rating might output different amounts of light, depending upon brand or model number; and the 1:10 ratio of power might not be always right. Similarly the conversion efficiency of LED bulb is not always the same.
So one needs to be careful that one is not outputting far brighter light from a safelight...the LUMEN rating is what needs to be close, so as to get about 'the same' amount of light.
One 60W incandescent bulb outputs 580 Lumens
another 60W incandescent bult outputs 520 Lumens
One 60 Watt equivalent LED bulb consumes 9 Wattsa and outputs 750 Lumens
another 60 Watt equivalent LED bulb consumes 7 Watts and outputs 810 Lumens