MicrobeHunter.com Microscopy Forum

My photographs and video's always have a yellowish/brown background, which I do not see in other footage. This is even the case with clear water between the specimen glasses and relatively independent of the brightness of the light I use. See attached photograph (sharpened too much, but this photo is only to illustrate my point). Does everyone use a blue filter or something? It could be the halogen lamp (of which I tried different brands), but I can't find other colors then 'warm white'. I use a Panasonic C9 camera and an adapter with 50% relay lens. I don't think the camera is the problem, because the bird photographs I take are fine.

Sorry, I can find no reference to a Panasonic C9 camera
... Do you mean the Panasonic DC G9

Whatever ... It should be simply a matter of selecting/adjusting ‘White Balance’
[this can be done either in camera, or in post-processing]

MichaelG.

Hi Jan,
halogen light has a yellow tint and often is used with a blue filter on top of the field iris.
Camera light meters expect an object of the brightness of an 18% grey card. In bright field microscopy you have a lot of bright background and your little object. To get a good exposure you have to use exposure compensation like +1 or +2 stops.
After the shot you can set your white point on the area you want white. But first you should optimize the exposure.

Bob

Do you mean the Panasonic DC G9

Sorry, I meant Panasonic Lumix G9.
Thanks for the answers. I will correct my exposure and take look at the white balance. And buy a blue filter.

It looks to be a superb camera : https://camerajabber.com/panasonic-g9-review/

I'm sure that the White Balance setting will do what's needed.

MichaelG.

Re yellow photos - you can do one of four things to fix the background colour:

1) use a blue filter - they are sometimes called daylight filters, and use the max brightness of your bulbs
2) You can set you camera white balance to tungsten about 3200 K
3) You can fix the colour quickly if you use Photoshop - in camera RAW there is a white balance tool, click on a gray area and the background will become white with equal RGB numbers . This requires post processing with software and provides the best result
4) You can use a daylight LED light for your microscope they make them for a few hundred dollars and sell them on ebay - I have purchased two of them for older microscopes.

Thanks for the answers. I have changed the white balance and bought a blue filter. Already much better, but I am still searching for the optimum setup.

RobBerdan wrote: ↑

Mon Jan 20, 2020 5:18 am

Re yellow photos - you can do one of four things to fix the background colour:

1) use a blue filter - they are sometimes called daylight filters, and use the max brightness of your bulbs
2) You can set you camera white balance to tungsten about 3200 K
3) You can fix the colour quickly if you use Photoshop - in camera RAW there is a white balance tool, click on a gray area and the background will become white with equal RGB numbers . This requires post processing with software and provides the best result
4) You can use a daylight LED light for your microscope they make them for a few hundred dollars and sell them on ebay - I have purchased two of them for older microscopes.

A slide that has been stained with toluidine blue? not the best example of how to beat the yellows.

The light that are used on microscopes has a yellowish tin to it. If you White balance your camera it will make it proper color.

Light color is a function of filament temperature: as you dim your light, the filament gets cooler and redder and gets whiter and hotter with increased brightness.

A single blue filter will only work for a specific range of brightness; on either side of that range, you'll need different blue filters.

Your camera has a range of white balance adjustments, but those will NOT change as a function of filament temperature. You'll have to readjust white balance every time you dim or amplify lighting. It'll be a constant dance of white balance adjustment and blue filter swaps ever time you adjust your lighting.

The modern LED light is a godsend in this respect. A high quality LED light will provide white light regardless of intensity and you can customize, "set and forget", your camera's white balance setting once you have it dialed in.

You can shoot in RAW and adjust white balance in post processing.

The previous posts cover a host of very good options. I am not familiar with your camera but many medium have a custom white balance option that augments the presets. You might want to check your camera manual and see if it does and try it. The best alternative has already been suggested is to shoot in raw and correct in post. I use DXO Photolab for most adjustments and finish off with the Topaz suite.