colloidal gold nanometer size, shape and color chart

[kephra]

You can judge particle size distribution by looking at the reflected light instead of the transmitted light.  The less spread in particle size, the less muddy (turbid) the solution looks. You won't see that by looking through it. 

Less turbidity equal small range of particle sizes.

[samiam]

This week I made an experiment to improve my colloidal gold making process for 500 ml.

Everything else keeping the same, I moved my anode closer to the cathode ( from 4.5 cm to 2.5 cm)
The results were dramatic.

The first batch (4.5 cm) took about 70 min to finish.
It started at 200 ma, slowly dropped to 185 ma, and started to rise again. Left on the photo.

The second batch (2.5 cm) started at 250 ma, dropped then to 200 ma before starting to rise.
This took about 50 min. and the color was a lot darker. Right on the photo.

I guess when the current is at the lowest point, this is a sign the batch is ready.

The shorter distance between the electrodes seems an improvement. At least the process is shorter and the color is darker.
But how about the particle size?

I am puzzled by the fact that the two processes seem to have their own dynamics and are ready at the lowest amp rate.

Could it be that the second batch not just produced more particles but also bigger ones, and that the first has in fact the superior quality.
Because the orange like color suggests smaller particles? 


PS. I found another chart for particle size and color. Very informative, but still impossible to know what my particle size in fact is.
My conclusion;  is it fine as long it is red.

Click and scroll to the bottom.

http://www.ansci.wisc.edu/facstaff/Faculty/pages/albrecht/albrecht_web/Programs/microscopy/colloid.html

according to the chart(picture) from this link, the one on the left(orange shade colloidal gold) seem to be in larger particle size than the red one on the right..

[mraluma415]

This week I made an experiment to improve my colloidal gold making process for 500 ml.

Everything else keeping the same, I moved my anode closer to the cathode ( from 4.5 cm to 2.5 cm)
The results were dramatic.

The first batch (4.5 cm) took about 70 min to finish.
It started at 200 ma, slowly dropped to 185 ma, and started to rise again. Left on the photo.

The second batch (2.5 cm) started at 250 ma, dropped then to 200 ma before starting to rise.
This took about 50 min. and the color was a lot darker. Right on the photo.

I guess when the current is at the lowest point, this is a sign the batch is ready.

The shorter distance between the electrodes seems an improvement. At least the process is shorter and the color is darker.
But how about the particle size?

I am puzzled by the fact that the two processes seem to have their own dynamics and are ready at the lowest amp rate.

Could it be that the second batch not just produced more particles but also bigger ones, and that the first has in fact the superior quality.
Because the orange like color suggests smaller particles? 


PS. I found another chart for particle size and color. Very informative, but still impossible to know what my particle size in fact is.
My conclusion;  is it fine as long it is red.

Click and scroll to the bottom.

http://www.ansci.wisc.edu/facstaff/Faculty/pages/albrecht/albrecht_web/Programs/microscopy/colloid.html

according to the chart(picture) from this link, the one on the left(orange shade colloidal gold) seem to be in larger particle size than the red one on the right..

When you say "seems to be", does that mean you are basing that observation on your experience as a nano technician, or rather looking at it from a theoretical perspective based on the colors appeal.

The colors are much darker than they look in such a small, shallow glass vial if compared to your larger flasks and their corresponding color. They do seem to white balance and contrast the scientific photos to get as close as possible to the finely tuned tints.