Which Green?

Product	Part Number	Brightness 10min (mcd/m2)	Brightness 60min (mcd/m2)	Grade	Particle Size (micron)
Ultra Green V10	PDPGA	945	126	Grade 0	55-85
Ultra Green V10-B	PDZGB	798	105	Grade 0	35-65
Ultra Green V10-C	PDZGC	646	85	Grade 0	15-35
Ultra Green V10-D	PDZGD	454	60	Grade 0	10-20
Ultra Green V10-E	PDZGE	262	35	Grade 0	5-15
Ultra Green V10-F	PDZGF	196	25	Grade 0	2-8
Ultra Green	PDUG	607	80	Grade 1	35-65
Green	PDEG	319	41	Grade 5	15-40
V10 Coated	PCPG	945	126	Grade 0	56-86
Daytime Green	PDDG	320	38	Grade 3	20-40
Green Sand	PSUG	~400	~40	Grade 3	250-500

Grade

Green strontium aluminate phosphorescent pigment is currently sold in 7 grades.  At the wholesale level, the difference is brightness vs. cost.  As you can see from above, there is a large difference in brightness between grades.  Over 98% of phosphorescent material produced is Grade 4 and 5, which is available from dozens of discount sources.  Glow Inc. purchases over 90% of the Grade 0 manufactured in the world.  

Particle Size

Phosphorescent pigments are not a dye.  They maintain their original shape and they do not color the medium around them.  Larger particles, within a grade, are brighter.  However, larger particle sizes create rough textured surfaces.  On thin applications, they can also create a speckled look when observed closely.  Therefore, smaller particle sizes look and feel smoother at the cost of brightness.  Additionally, smaller particle sizes are more likely to work in air brushes and printers.  Smaller particle sizes are also less likely to settle in their medium.

For an in-depth examination of the speckled appearance when using large particles, consider reading our technical article "The Grainy Issue".

Note:  It is a common misconception that all strontium aluminate pigments are of similar grade and that particle size is the sole determinant of brightness.  Another myth is that grade is the same as particle size.  As you can see from the chart above, this is not true.  A comparison of our Sample Pack to other manufacturers will quickly show which grade they are selling.

Backgrounds

Bright white backgrounds are less likely to show the above-mentioned speckled appearance for large particle pigments.  White will also reflect the glow on thin applications, improving performance.  If possible, stay clear from dark backgrounds.

Coated

Coated Pigments have a thin protective layer added to each individual particle.  This prevents them from dissolving in water or being damaged by some acids.  They are also more durable.

Daytime

Daytime powders are a mix of phosphorescent pigment and fluorescent pigment.  The result is a product that glows in the dark in one color and is vibrant in the light in different color.

Sample Pack

For manufacturers, Glow Inc. has a Green Powder Sample Pack which includes all eleven of the above products for comparison.

A request from the author:

Glow Inc. has always been at the forefront of providing free technical information on the subject of "glow in the dark".  Most recently, we added the Glow in the Dark Forum so that customers can add to this free information base.

However, we are in desperate need of exposure on the Internet.  If you enjoyed this article, please consider putting a link to it on your website, blog, or your favorite forum.