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ArcticMyst Security by Avery

Green VS 445 really??

Ablaze

0
Joined
Oct 19, 2011
Messages
462
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0
Hmm.. it appears, after further research, that the data table he used is a standard that has been in effect since 1924.

So now I'm back to not knowing why it appears to be off for 450nm. All I know is that it is.
 





Joined
Sep 29, 2011
Messages
800
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0
Well like we've all said. Brightness is a matter of perspective from person to person. The chart that it is based off has set variables. The chart refers to brightness in a specific controlled environment I'm sure if we looked at a 1W 445 next to a 175mW 532 in an environment with no particulate matter in the air for the beams to reflect off of the green would start looking brighter. Chances are that the chart it's based on assumes an environment with no particulate matter suspended in the air and it's just using the rayleigh scattering rate of air (as in atmospheric gases without any suspended particles.) The more I think about it the more I am almost positive that is the case.
What does everyone else think about my theory?
 
Last edited:

rhd

0
Joined
Dec 7, 2010
Messages
8,475
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0
If you guys tag "?chromacompat=yes" to the end of the URL, it uses a different dataset that some people prefer.

I can't remember if it's "yes" or "on", but it's one of those :)

And if your URL already has it, try turning it off :)
 
Joined
Sep 29, 2011
Messages
800
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0
If you guys tag "?chromacompat=yes" to the end of the URL, it uses a different dataset that some people prefer.

I can't remember if it's "yes" or "on", but it's one of those :)

And if your URL already has it, try turning it off :)

I was wondering when you would wander on in here :yh:
First I want to start off by saying thanks. I actually use the calculator on a regular basis.
The second thing I wanted to ask was what you think about the theory in my last post about how the chart probably assumes an atmosphere with little to no particulate matter in the air as well as low humidity. Would you say that's a reasonable assumption?

EDIT- Can you send me a link to the specific chart you used. I know there are a bunch of relative brightness charts around but I'd like to take a look at your source to see if there is any mention of environmental factors.
 
Last edited:

Ablaze

0
Joined
Oct 19, 2011
Messages
462
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If you guys tag "?chromacompat=yes" to the end of the URL, it uses a different dataset that some people prefer.
I just tried that and it does predict a brighter 450nm

However, there is something pretty major going on here. When I use actual lasers this appears approximately equal, with the blue perhaps being brighter.
 
Joined
Nov 7, 2008
Messages
5,725
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0
Perceived brightness IS subjective just as Jerry says, AND the sensitivity of the eye at various wavelengths varies from person to person and from environment to environment. I always have and will continue to view any "tool" that claims to be able to accurately quantify that which is subjective as being an impossibility.

As an example, with laser shows I've found that 2W of blue mates rather well with 1.5W of green.. the blues are not quite as bright as the greens, but they're FAR from dim. According to the charts the greens should walk all over the blues, but the difference isn't nearly as much as the software would suggest, at least to my eyes. Someone else's perspective will be different, especially when we're talking about deep blues and violets. Some people are nearly flash-blinded by 25mW of 405nm reflecting off of a wall, while others perceive that much 405nm as very dim.
 

rhd

0
Joined
Dec 7, 2010
Messages
8,475
Points
0
I was wondering when you would wander on in here :yh:
First I want to start off by saying thanks. I actually use the calculator on a regular basis.
The second thing I wanted to ask was what you think about the theory in my last post about how the chart probably assumes an atmosphere with little to no particulate matter in the air as well as low humidity. Would you say that's a reasonable assumption?

EDIT- Can you send me a link to the specific chart you used. I know there are a bunch of relative brightness charts around but I'd like to take a look at your source to see if there is any mention of environmental factors.

I only have the raw data saved - but presumably with some googling of the figures, you can back-track the original chart. Note that these are the figures for the "chromacompat" flag on. Without that flag, it uses CIE tables that are linked at the bottom of the calculator itself.

Then, in short, NO, it does not take any environmental factors into consideration at all. The figures here (below or in the CIE tables) only account for the actual wavelength perception. In order to factor in Raliegh scattering, the calculator applies an additional calculation. From memory, that calculation is often X^4. However, NASA has refined this to X^4.08. You could look up the study NASA did re: the Raleigh figure being 4.08, and see if they made any presumptions regarding humidity, etc, but I don't think that would come into play at that stage. In fact, it probably shouldn't come into play at any stage, given that this is a tool for finding relative brightness - so the comparison would be presumed to occur in the same environmental conditions for both wavelengths you're comparing. Unless environment changed the relative impact of Raleigh scattering, I can't see it mattering.

Again, I don't have the math in front of me, but I'm pretty sure that's the calculation.

Ok, sorry for the long quote here :
(second column is wavelength, third is perceived brightness relative to 1, which occurs at 555nm)

Code:
1	380	0.0002
2	381	0.00022821
3	382	0.00026109
4	383	0.00029936
5	384	0.00034387
6	385	0.00039556
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371	750	0.00012
 
Last edited:
Joined
Sep 29, 2011
Messages
800
Points
0
I only have the raw data saved - but presumably with some googling of the figures, you can back-track the original chart. Note that these are the figures for the "chromacompat" flag on. Without that flag, it uses CIE tables that are linked at the bottom of the calculator itself.

Then, in short, NO, it does not take any environmental factors into consideration at all. The figures here (below or in the CIE tables) only account for the actual wavelength perception. In order to factor in Raliegh scattering, the calculator applies an additional calculation. From memory, that calculation is often X^4. However, NASA has refined this to X^4.08. You could look up the study NASA did re: the Raleigh figure being 4.08, and see if they made any presumptions regarding humidity, etc, but I don't think that would come into play at that stage. In fact, it probably shouldn't come into play at any stage, given that this is a tool for finding relative brightness - so the comparison would be presumed to occur in the same environmental conditions for both wavelengths you're comparing. Unless environment changed the relative impact of Raleigh scattering, I can't see it mattering.

Again, I don't have the math in front of me, but I'm pretty sure that's the calculation.

Ok, sorry for the long quote here :
(second column is wavelength, third is perceived brightness relative to 1, which occurs at 555nm)

Code:
1	380	0.0002
2	381	0.00022821
3	382	0.00026109
4	383	0.00029936
5	384	0.00034387
6	385	0.00039556
7	386	0.00045544
8	387	0.00052462
9	388	0.00060428
10	389	0.00069565
11	390	0.0008
12	391	0.00091635
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15	394	0.0013611
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17	396	0.0017508
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20	399	0.0025011
21	400	0.0028
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24	403	0.0038268
25	404	0.0042256
26	405	0.0046562
27	406	0.0051216
28	407	0.0056248
29	408	0.0061695
30	409	0.0067597
31	410	0.0074
32	411	0.0081451
33	412	0.0089555
34	413	0.0098322
35	414	0.010774
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215	594	0.7074965
216	595	0.6949
217	596	0.6822192
218	597	0.6694716
219	598	0.6566744
220	599	0.6438448
221	600	0.631
222	601	0.6181555
223	602	0.6053144
224	603	0.5924756
225	604	0.5796379
226	605	0.5668
227	606	0.5539611
228	607	0.5411372
229	608	0.5283528
230	609	0.5156323
231	610	0.503
232	611	0.4904688
233	612	0.4780304
234	613	0.4656776
235	614	0.4534032
236	615	0.4412
237	616	0.42908
238	617	0.417036
239	618	0.405032
240	619	0.393032
241	620	0.381
242	621	0.3689184
243	622	0.3568272
244	623	0.3447768
245	624	0.3328176
246	625	0.321
247	626	0.3093381
248	627	0.2978504
249	628	0.2865936
250	629	0.2756245
251	630	0.265
252	631	0.2547632
253	632	0.2448896
254	633	0.2353344
255	634	0.2260528
256	635	0.217
257	636	0.2081616
258	637	0.1995488
259	638	0.1911552
260	639	0.1829744
261	640	0.175
262	641	0.1672235
263	642	0.1596464
264	643	0.1522776
265	644	0.1451259
266	645	0.1382
267	646	0.1315003
268	647	0.1250248
269	648	0.1187792
270	649	0.1127691
271	650	0.107
272	651	0.1014762
273	652	0.09618864
274	653	0.09112296
275	654	0.08626485
276	655	0.0816
277	656	0.07712064
278	657	0.07282552
279	658	0.06871008
280	659	0.06476976
281	660	0.061
282	661	0.05739621
283	662	0.05395504
284	663	0.05067376
285	664	0.04754965
286	665	0.04458
287	666	0.04175872
288	667	0.03908496
289	668	0.03656384
290	669	0.03420048
291	670	0.032
292	671	0.02996261
293	672	0.02807664
294	673	0.02632936
295	674	0.02470805
296	675	0.0232
297	676	0.02180077
298	677	0.02050112
299	678	0.01928108
300	679	0.01812069
301	680	0.017
302	681	0.01590379
303	682	0.01483718
304	683	0.01381068
305	684	0.01283478
306	685	0.01192
307	686	0.01106831
308	687	0.01027339
309	688	0.009533311
310	689	0.008846157
311	690	0.00821
312	691	0.007623781
313	692	0.007085424
314	693	0.006591476
315	694	0.006138485
316	695	0.005723
317	696	0.005343059
318	697	0.004995796
319	698	0.004676404
320	699	0.004380075
321	700	0.004102
322	701	0.003838453
323	702	0.003589099
324	703	0.003354219
325	704	0.003134093
326	705	0.002929
327	706	0.002738139
328	707	0.002559876
329	708	0.002393244
330	709	0.002237275
331	710	0.002091
332	711	0.001953587
333	712	0.00182458
334	713	0.00170358
335	714	0.001590187
336	715	0.001484
337	716	0.001384496
338	717	0.001291268
339	718	0.001204092
340	719	0.001122744
341	720	0.001047
342	721	0.00097659
343	722	0.000911109
344	723	0.000850133
345	724	0.000793238
346	725	0.00074
347	726	0.000690083
348	727	0.00064331
349	728	0.000599496
350	729	0.000558455
351	730	0.00052
352	731	0.000483914
353	732	0.000450053
354	733	0.000418345
355	734	0.000388718
356	735	0.0003611
357	736	0.000335384
358	737	0.00031144
359	738	0.000289166
360	739	0.000268454
361	740	0.0002492
362	741	0.000231302
363	742	0.000214686
364	743	0.000199288
365	744	0.000185048
366	745	0.0001719
367	746	0.000159778
368	747	0.000148604
369	748	0.000138302
370	749	0.000128793
371	750	0.00012

Thanks for the info. :)
 

SOG

0
Joined
Jun 13, 2011
Messages
109
Points
0
thanks for the information, I have always wonder how much brighter green could be...
But I am sure lens, air quality, battery power, laser actual output, temperature... etc all comes into play.
 
Joined
Nov 7, 2008
Messages
5,725
Points
0
Ok, sorry for the long quote here :
(second column is wavelength, third is perceived brightness relative to 1, which occurs at 555nm)

Code:
1    380    0.0002
2    381    0.00022821
3    382    0.00026109
4    383    0.00029936
5    384    0.00034387
6    385    0.00039556
7    386    0.00045544
8    387    0.00052462
9    388    0.00060428
10    389    0.00069565
11    390    0.0008
12    391    0.00091635
13    392    0.0010477
14    393    0.0011955
15    394    0.0013611
16    395    0.0015457
17    396    0.0017508
18    397    0.0018776
19    398    0.0022273
20    399    0.0025011
21    400    0.0028
22    401    0.0031159
23    402    0.0034576
24    403    0.0038268
25    404    0.0042256
26    405    0.0046562
27    406    0.0051216
28    407    0.0056248
29    408    0.0061695
30    409    0.0067597
31    410    0.0074
32    411    0.0081451
33    412    0.0089555
34    413    0.0098322
35    414    0.010774
36    415    0.011779
37    416    0.012842
38    417    0.013956
39    418    0.015111
40    419    0.016297
41    420    0.0175
42    421    0.018582
43    422    0.019645
44    423    0.020683
45    424    0.021694
46    425    0.022678
47    426    0.023636
48    427    0.024572
49    428    0.02549
50    429    0.026397
51    430    0.0273
52    431    0.028335
53    432    0.029383
54    433    0.030442
55    434    0.03151
56    435    0.032584
57    436    0.033661
58    437    0.034735
59    438    0.035803
60    439    0.03686
61    440    0.0379
62    441    0.038838
63    442    0.039752
64    443    0.040646
65    444    0.041524
66    445    0.042391
67    446    0.043252
68    447    0.044116
69    448    0.04499
70    449    0.045881
71    450    0.0468
72    451    0.047743
73    452    0.048733
74    453    0.049785
75    454    0.05091
76    455    0.052122
77    456    0.053435
78    457    0.054864
79    458    0.056424
80    459    0.058131
81    460    0.06
82    461    0.06260197
83    462    0.06527752
84    463    0.06804208
85    464    0.07091109
86    465    0.0739
87    466    0.077016
88    467    0.0802664
89    468    0.0836668
90    469    0.0872328
91    470    0.09098
92    471    0.09491755
93    472    0.09904584
94    473    0.1033674
95    474    0.1078846
96    475    0.1126
97    476    0.117532
98    477    0.1226744
99    478    0.1279928
100    479    0.1334528
101    480    0.13902
102    481    0.1446764
103    482    0.1504693
104    483    0.1564619
105    484    0.1627177
106    485    0.1693
107    486    0.1762431
108    487    0.1835581
109    488    0.1912735
110    489    0.199418
111    490    0.20802
112    491    0.2171199
113    492    0.2267345
114    493    0.2368571
115    494    0.2474812
116    495    0.2586
117    496    0.2701849
118    497    0.2822939
119    498    0.2950505
120    499    0.308578
121    500    0.323
122    501    0.3384021
123    502    0.3546858
124    503    0.3716986
125    504    0.3892875
126    505    0.4073
127    506    0.4256299
128    507    0.4443096
129    508    0.4633944
130    509    0.4829395
131    510    0.503
132    511    0.5235693
133    512    0.544512
134    513    0.56569
135    514    0.5869653
136    515    0.6082
137    516    0.6293456
138    517    0.6503068
139    518    0.6708752
140    519    0.6908424
141    520    0.71
142    521    0.7281852
143    522    0.7454636
144    523    0.7619694
145    524    0.7778368
146    525    0.7932
147    526    0.8081104
148    527    0.8224962
149    528    0.8363068
150    529    0.8494916
151    530    0.862
152    531    0.8738108
153    532    0.8849624
154    533    0.8954936
155    534    0.9054432
156    535    0.9148501
157    536    0.9237348
158    537    0.9320924
159    538    0.9399226
160    539    0.9472252
161    540    0.954
162    541    0.9602561
163    542    0.9660074
164    543    0.9712606
165    544    0.9760225
166    545    0.9803
167    546    0.9840924
168    547    0.9874182
169    548    0.9903128
170    549    0.9928116
171    550    0.9949501
172    551    0.9967108
173    552    0.9980983
174    553    0.999112
175    554    0.9997482
176    555    1
177    556    0.9998567
178    557    0.9993046
179    558    0.9983255
180    559    0.9968987
181    560    0.995
182    561    0.9926005
183    562    0.9897426
184    563    0.9864444
185    564    0.9827241
186    565    0.9786
187    566    0.9740837
188    567    0.9691712
189    568    0.9638568
190    569    0.9581349
191    570    0.952
192    571    0.9454504
193    572    0.9384992
194    573    0.9311628
195    574    0.9234576
196    575    0.9154
197    576    0.9070064
198    577    0.8982772
199    578    0.8892048
200    579    0.8797816
201    580    0.87
202    581    0.8598613
203    582    0.849392
204    583    0.838622
205    584    0.8275813
206    585    0.8163
207    586    0.8047947
208    587    0.793082
209    588    0.781192
210    589    0.7691547
211    590    0.757
212    591    0.7447541
213    592    0.7324224
214    593    0.7200036
215    594    0.7074965
216    595    0.6949
217    596    0.6822192
218    597    0.6694716
219    598    0.6566744
220    599    0.6438448
221    600    0.631
222    601    0.6181555
223    602    0.6053144
224    603    0.5924756
225    604    0.5796379
226    605    0.5668
227    606    0.5539611
228    607    0.5411372
229    608    0.5283528
230    609    0.5156323
231    610    0.503
232    611    0.4904688
233    612    0.4780304
234    613    0.4656776
235    614    0.4534032
236    615    0.4412
237    616    0.42908
238    617    0.417036
239    618    0.405032
240    619    0.393032
241    620    0.381
242    621    0.3689184
243    622    0.3568272
244    623    0.3447768
245    624    0.3328176
246    625    0.321
247    626    0.3093381
248    627    0.2978504
249    628    0.2865936
250    629    0.2756245
251    630    0.265
252    631    0.2547632
253    632    0.2448896
254    633    0.2353344
255    634    0.2260528
256    635    0.217
257    636    0.2081616
258    637    0.1995488
259    638    0.1911552
260    639    0.1829744
261    640    0.175
262    641    0.1672235
263    642    0.1596464
264    643    0.1522776
265    644    0.1451259
266    645    0.1382
267    646    0.1315003
268    647    0.1250248
269    648    0.1187792
270    649    0.1127691
271    650    0.107
272    651    0.1014762
273    652    0.09618864
274    653    0.09112296
275    654    0.08626485
276    655    0.0816
277    656    0.07712064
278    657    0.07282552
279    658    0.06871008
280    659    0.06476976
281    660    0.061
282    661    0.05739621
283    662    0.05395504
284    663    0.05067376
285    664    0.04754965
286    665    0.04458
287    666    0.04175872
288    667    0.03908496
289    668    0.03656384
290    669    0.03420048
291    670    0.032
292    671    0.02996261
293    672    0.02807664
294    673    0.02632936
295    674    0.02470805
296    675    0.0232
297    676    0.02180077
298    677    0.02050112
299    678    0.01928108
300    679    0.01812069
301    680    0.017
302    681    0.01590379
303    682    0.01483718
304    683    0.01381068
305    684    0.01283478
306    685    0.01192
307    686    0.01106831
308    687    0.01027339
309    688    0.009533311
310    689    0.008846157
311    690    0.00821
312    691    0.007623781
313    692    0.007085424
314    693    0.006591476
315    694    0.006138485
316    695    0.005723
317    696    0.005343059
318    697    0.004995796
319    698    0.004676404
320    699    0.004380075
321    700    0.004102
322    701    0.003838453
323    702    0.003589099
324    703    0.003354219
325    704    0.003134093
326    705    0.002929
327    706    0.002738139
328    707    0.002559876
329    708    0.002393244
330    709    0.002237275
331    710    0.002091
332    711    0.001953587
333    712    0.00182458
334    713    0.00170358
335    714    0.001590187
336    715    0.001484
337    716    0.001384496
338    717    0.001291268
339    718    0.001204092
340    719    0.001122744
341    720    0.001047
342    721    0.00097659
343    722    0.000911109
344    723    0.000850133
345    724    0.000793238
346    725    0.00074
347    726    0.000690083
348    727    0.00064331
349    728    0.000599496
350    729    0.000558455
351    730    0.00052
352    731    0.000483914
353    732    0.000450053
354    733    0.000418345
355    734    0.000388718
356    735    0.0003611
357    736    0.000335384
358    737    0.00031144
359    738    0.000289166
360    739    0.000268454
361    740    0.0002492
362    741    0.000231302
363    742    0.000214686
364    743    0.000199288
365    744    0.000185048
366    745    0.0001719
367    746    0.000159778
368    747    0.000148604
369    748    0.000138302
370    749    0.000128793
371    750    0.00012

In light of these tables, can anyone explain to me why it is that, when I have polled actual living, breathing people in the same environment (same room, same particulate matter, same ambient light levels) I get different responses regarding the perceived brightness of various short-wavelength sources? I even get different responses concerning their actual perceived hue at short wavelengths, with many people saying that 445nm (for example) appears more purple than blue and many other people saying the opposite.. and I have asked lots of people about this, both directly and indirectly, for my own research.

How do these tables take into account the natural variation in vision sensitivity that occurs from person to person? It's a well-known fact that people perceive colors differently from one another, color-blindness is a very well-known example of this.

Given that none of the tables or data I've seen on this topic take things like natural variation and environmental concerns into account, what usefulness does this data provide other than a very rough guide? Maybe there's something I'm missing here, but when there are so many variables involved in this issue that cannot be precisely quantified, I can't see the point in trying to calculate to multiple decimal places. The whole thing inherently lacks true precision from my view.
 
Last edited:

Things

0
Joined
May 1, 2007
Messages
7,517
Points
0
That's exactly in Elektro, a "rough guide". There is no way any fixed data sets would account for the whole human population, EVERYONE is going to perceive brightness and wavelength differently.

The data sets are theoretical, and are most likely just mathematically generated, taking no human perception into account at all.

I'm always weary of these brightness comparison things.

I have 300mW 640nm, 400mW 532nm and 1W 445nm lasers in my laser projector, and to me, all combined it looks damn near white with an ever so slight blue-ish tinge, even with the red 100mW less than green!
 
Joined
Sep 29, 2011
Messages
800
Points
0
In light of these tables, can anyone explain to me why it is that, when I have polled actual living, breathing people in the same environment (same room, same particulate matter, same ambient light levels) I get different responses regarding the perceived brightness of various short-wavelength sources? I even get different responses concerning their actual perceived hue at short wavelengths, with many people saying that 445nm (for example) appears more purple than blue and many other people saying the opposite.. and I have asked lots of people about this, both directly and indirectly, for my own research.

How do these tables take into account the natural variation in vision sensitivity that occurs from person to person? It's a well-known fact that people perceive colors differently from one another, color-blindness is a very well-known example of this.

Given that none of the tables or data I've seen on this topic take things like natural variation and environmental concerns into account, what usefulness does this data provide other than a very rough guide? Maybe there's something I'm missing here, but when there are so many variables involved in this issue that cannot be precisely quantified, I can't see the point in trying to calculate to multiple decimal places. The whole thing inherently lacks true precision from my view.

Well that is the question we have all been asking. We (or I) have come to the conclusion that none of these charts take into account variables such as particulate matter, humidity, pollution etc. If you were to shine lasers into a tank containing
78.084% nitrogen
20.946% oxygen
0.9340% argon
0.039% carbon dioxide

(The main composition of the earths atmosphere) and nothing else than you would get results much closer to the brightness charts because to come up with the charts they use the rayleigh scattering of those molecules. Really when you think about it those charts are kind of ridiculous considering you're never going to be in an environment where there is no particulate matter aside from a lab setting.
 
Last edited:
Joined
Apr 2, 2009
Messages
10,662
Points
113
Good thread with lots of great input.
This is one of the most often questions from the DIY PJ builders;
Also what your particular camera 'sees' can vary a lot.
My avatar shows another -thing--the colors change when viewing diff. waveleghts side by side. A 532 turns quite yellow to me when in the presence of an Argon laser.
My avatar shows two C-mount Jetlasers 200mW 635s_(peak is ~300mW). note the diff. between the two.
The green is a 100mW overspec JETL 532 250mW and the 445 is a 1.2W.


This was taken on a nite with a very slight bit of fog in the air, almost none IMO.
 
Last edited:




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