Convert film sizes from scanning to printing

scanFilm.md

library(magrittr)
library(dplyr)
library(knitr)

ratio <- 1 / 25.4  # in to mm conversion ratio
df <- 
  expand.grid(edge = c("Short", "Long"),
              film = c("35mm", "6X6", "6X7", "4X5"),
              dpiScan = 800 * (2 ^ seq(0, 3)),
              dpiPrint = c(300)) %>% 
  mutate(mm = case_when(film == "35mm" & edge == "Short" ~ 24,
                        film == "35mm" & edge == "Long" ~ 36,
                        film == "6X6" ~ 56,
                        film == "6X7" & edge == "Short" ~ 56,
                        film == "6X7" & edge == "Long" ~ 70,
                        film == "4X5" & edge == "Short" ~ 95,
                        film == "4X5" & edge == "Long" ~ 120)) %>% 
  mutate(pixels = mm * ratio * dpiScan) %>% 
  mutate(print = pixels / dpiPrint)
df <-
  inner_join(df %>% filter(edge == "Short"),
             df %>% filter(edge == "Long"),
             by = c("film", "dpiScan", "dpiPrint"),
             suffix = c("Short", "Long")) %>% 
  mutate(mp = mmShort * mmLong * (ratio * dpiScan / 1e3)^2) %>% 
  select(film, dpiScan, mp, pixelsShort, pixelsLong, dpiPrint, printShort, printLong) %>% 
  arrange(film, -dpiScan, -dpiPrint)
df %>% 
  kable(align = "lccccccc", digits = 0)

film	dpiScan	mp	pixelsShort	pixelsLong	dpiPrint	printShort	printLong
35mm	6400	55	6047	9071	300	20	30
35mm	3200	14	3024	4535	300	10	15
35mm	1600	3	1512	2268	300	5	8
35mm	800	1	756	1134	300	3	4
6X6	6400	199	14110	14110	300	47	47
6X6	3200	50	7055	7055	300	24	24
6X6	1600	12	3528	3528	300	12	12
6X6	800	3	1764	1764	300	6	6
6X7	6400	249	14110	17638	300	47	59
6X7	3200	62	7055	8819	300	24	29
6X7	1600	16	3528	4409	300	12	15
6X7	800	4	1764	2205	300	6	7
4X5	6400	724	23937	30236	300	80	101
4X5	3200	181	11969	15118	300	40	50
4X5	1600	45	5984	7559	300	20	25
4X5	800	11	2992	3780	300	10	13