At nearly 70, I can still see eggs, but I have to work harder than my young students and employees, and when we are measuring areas of open brood for research, I defer to the youngest on the crew for accuracy.
I've tried magnifiers, flashlights, cameras - but nothing really helped, other than turning my back to sun and using it to illuminate the bottom of cells. And the dark cells were still a challenge. Overcast days, forget it.
This summer, I solved the problem. Yellow lenses in glasses!
Cheapest source, buy Safety Glasses with yellow lenses sold in most any hardware store, box stores like Lowes and Home Depot. Similar glasses, usually more expensive, are found in the gun/archery section of Sporting Good stores. And, these are also sold as Night Driving glasses.
They reportedly improve contrast.
We were starting a new experiment on a cool, cloudy day, and the crew was measuring areas of capped and uncapped brood. Once again, how do us old timers see the eggs on overcast days? And then I thought of yellow glasses.
Not only that, but even the youngest employee said it was like night and day in dark combs. Quick trip back to hardware stores, and everyone was using yellow glasses. If its really overcast and the combs old and dark, combine the yellow glasses with one of the new high lumens output LED, pencil flashlights.
Between the two, eggs easy to see in any comb.
Dato de Jerry Bromenshenk via Bee-L la foto es de mi elección ;)