EXPOSURE 69 
wemrene lransparency, Black iy Wie vislec hess o\6 aa) « 8 
LATE CUNY CL oa IE A enn eT SUT i RN Mia uta 25 
PPT PA SEY MUNIN a) dal fis ooh 4 Alb Ai aie tamara a eT VeRaNeN sta aE ablsia tego 10 
Pinion (Chloro-bromide. oo iy ea eas an = 
Perret Vic CG he Sk SAM te vd LIA 32 
Merion Gelatine-chioride |... 012 COMM a UAT al ol 32 
WARS OTA oh ial 4) aay ee edat Sie i ck Gla S ROMAN a NREL SIMS NY Nat UU 0 Vale = 
Rete ENACT eS By UA ly 
Pasay (SI Let sane OMT CH An SN OM WW 
Beet WOOK WU ransparency . 1.) dies espe ees 3 
IPSEC CURIA NGS ae Ae SAMAR Suh Ue CoS OEY Ie 10 
oval otandand black ie oy Oe a ue nN ais em) el ie 8 
SSO SANA EE SmI STOO RU Aa NS ATAU Aa 3 
SiZinCley ec Resa beh ills MUR en aN USMS atu 3 
SAMOA G COMO GN CL oho ICS ut eT a Ae oe 4 
EPMO a iy Lk aL GS TAU eT Ani A 1 
Be eter eM en eS ACN ga LU AUS RE UE i 20 
In these tables the paper or plate with a factor number of 6 
requires twice the exposure of one with a factor of 3, under 
like conditions. 
COMPARISON OF PLATE SPEEDS.—Unfortunately, no com- 
mon agreement has been arrived at as to the marking of plate 
speeds, but the following table gives the usually accepted 
ratios between the various systems: 
wa 5 “4 i ea ow 
Hal E 2 fa E a Be pa 
5.4 8 17 8 8 c me 100 
7, 10 20 Hae 9 b 80 
9 SNe, 6 ONS cau vA OTN 65 
11 LOLS 25-5 4 10 ] 43 50 
14 Bi) 20 10.50 (20 ae ag 
17:5 26 32 3 ot 3 49 30 
