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Spots aka blemishes are the black spots that can be in any night vision tube. Tube manufacturers measure these and have allowances for what is and what isn't allowed in each Zone of the tube.
This information is found in the "Spot spec chart" for the tube grade you are purchasing.
For example-
Zone 1- 0
Zone 2- (2) .003
Zone 3- (2) .003 (1) .006
If you saw that, what would that mean?
It would mean that in the CENTER of the tube, the very center (Zone 1) no spots .003 or larger are allowed. It would mean that in Zone 2 which is the next outer band proceeding out from the center towards the edges, 2 spots that are .003 are allowed. And in Zone 3 which is the outer edge of the circle, 2 spots .003 are allowed as well as (1) spot .006 Think of the spot spec chart as your "worst case scenario"- they are 99% of time MUCH CLEANER than the spot spec chart shows.
The DATA SHEET(s) for the tube(s) in the unit you purchased will show the spot spec for that particular grade also if the tube is from L3 Harris or Elbit Systems of America.
Elbit sheets look like this in the spot spec area-
In the example above for an Elbit tube, this tube would be considered "clean" as it shows no spots .003 or larger. Note that it is the LEFT SIDE where you see all the 0's that shows YOUR results. The part on the right shows what is ALLOWED (maximum spots aka worst case scenario)
L3's data sheets are more convenient for the end user as it has the spot spec info as well as the little circles that designate the Zones.The L3 sheet is also easier for new people to comprehend as it has "limit" and "actual." "Actual" being what YOUR TUBE actually has, "limit" being the worst case scenario.
The little circles denote the Zones. Notice how small Zone 1 really is? It's VERY common for people to see something on the edge of Zone 2 and think it's in Zone 1. Here is where the DATA SHEET is the ultimate guide and the authority on what is and what isn't a spot and where it's located. Everything else is subjective.
"OK Robert, my data sheet shows clean like that but my tube has a couple tiny dots in Zone 2, what are they?"
They are most likely "pepper speck." Pepper speck is the teeny tiny stuff that NONE of the tube manufacturers chart- hence why you won't see it on anyone's data sheet. Outside, under real world usage, no one worries about pepper speck because you can rarely even see it outside. If you are however playing "sheetrock Ranger" and just staring at sheetrock inside your house, then yes you will find all the pepper speck.
So is something a pepper speck or is it a spot?
The answer is- What does the data sheet for your tube say? If it shows like it does above, then anything you are seeing is pepper speck, not an actual "spot."
Unfortunately, consumers don't always use the correct words and often call "pepper speck" a "spot." Remember a spot is .003 or larger and will show up on the data sheet.
Also, for the picky/OCD types that just want to play sheetrock ranger, an important thing to note is that tube pics will usually NOT show pepper speck because it's so small. That is a NORMAL tube pic, there is "that guy" that will zoom in, blare his IR and try to make a pepper speck larger. Again, what is the ultimate authority on this- YOUR DATA SHEET.
How do we (JRH) chart cosmetics in tubes?
When we build NV we look at both what the data sheet says as well as what we observe both with the test sets and also with the naked eye. If we see pepper speck, we will note that, if we see other tube cosmetic issues that are NOT on a data sheet like small lines, or areas with a little shadow, we will note that on your BUILD SHEET (different from your data sheet). So essentially we give you MORE INFO than what you will find on your data sheet alone, also more than what you would glean from a tube pic, as they rarely show pepper speck.
This info also helps us when we are hand selecting a unit for a customer as the customer is then also informed of pepper speck and other cosmetic issues that will not be covered in their tube data sheet.
This information is found in the "Spot spec chart" for the tube grade you are purchasing.
For example-
Zone 1- 0
Zone 2- (2) .003
Zone 3- (2) .003 (1) .006
If you saw that, what would that mean?
It would mean that in the CENTER of the tube, the very center (Zone 1) no spots .003 or larger are allowed. It would mean that in Zone 2 which is the next outer band proceeding out from the center towards the edges, 2 spots that are .003 are allowed. And in Zone 3 which is the outer edge of the circle, 2 spots .003 are allowed as well as (1) spot .006 Think of the spot spec chart as your "worst case scenario"- they are 99% of time MUCH CLEANER than the spot spec chart shows.
The DATA SHEET(s) for the tube(s) in the unit you purchased will show the spot spec for that particular grade also if the tube is from L3 Harris or Elbit Systems of America.
Elbit sheets look like this in the spot spec area-
In the example above for an Elbit tube, this tube would be considered "clean" as it shows no spots .003 or larger. Note that it is the LEFT SIDE where you see all the 0's that shows YOUR results. The part on the right shows what is ALLOWED (maximum spots aka worst case scenario)
L3's data sheets are more convenient for the end user as it has the spot spec info as well as the little circles that designate the Zones.The L3 sheet is also easier for new people to comprehend as it has "limit" and "actual." "Actual" being what YOUR TUBE actually has, "limit" being the worst case scenario.
The little circles denote the Zones. Notice how small Zone 1 really is? It's VERY common for people to see something on the edge of Zone 2 and think it's in Zone 1. Here is where the DATA SHEET is the ultimate guide and the authority on what is and what isn't a spot and where it's located. Everything else is subjective.
"OK Robert, my data sheet shows clean like that but my tube has a couple tiny dots in Zone 2, what are they?"
They are most likely "pepper speck." Pepper speck is the teeny tiny stuff that NONE of the tube manufacturers chart- hence why you won't see it on anyone's data sheet. Outside, under real world usage, no one worries about pepper speck because you can rarely even see it outside. If you are however playing "sheetrock Ranger" and just staring at sheetrock inside your house, then yes you will find all the pepper speck.
So is something a pepper speck or is it a spot?
The answer is- What does the data sheet for your tube say? If it shows like it does above, then anything you are seeing is pepper speck, not an actual "spot."
Unfortunately, consumers don't always use the correct words and often call "pepper speck" a "spot." Remember a spot is .003 or larger and will show up on the data sheet.
Also, for the picky/OCD types that just want to play sheetrock ranger, an important thing to note is that tube pics will usually NOT show pepper speck because it's so small. That is a NORMAL tube pic, there is "that guy" that will zoom in, blare his IR and try to make a pepper speck larger. Again, what is the ultimate authority on this- YOUR DATA SHEET.
How do we (JRH) chart cosmetics in tubes?
When we build NV we look at both what the data sheet says as well as what we observe both with the test sets and also with the naked eye. If we see pepper speck, we will note that, if we see other tube cosmetic issues that are NOT on a data sheet like small lines, or areas with a little shadow, we will note that on your BUILD SHEET (different from your data sheet). So essentially we give you MORE INFO than what you will find on your data sheet alone, also more than what you would glean from a tube pic, as they rarely show pepper speck.
This info also helps us when we are hand selecting a unit for a customer as the customer is then also informed of pepper speck and other cosmetic issues that will not be covered in their tube data sheet.