film: the chemical Process
A roll of film is essentially a combo of light-sensitive layers of gelatin and silver, all of which react together chemically when light reaches it. I won't go into the science of it all, but a reaction takes place and then the image you shot is imprinted onto the film, essentially freezing that moment of time. Think of those 90s, color-changing shirts that were all white until you went out into the sun, and then colors suddenly appeared to fill in the graphic. What a vibe. Film is just like that, but once light hits the film, it stays there forever, even after the shutter clicks and the curtain inside your camera shuts, keeping further light from getting in.
There's many types of film, both in size (35mm, 120, sheet), color (black and white, color), stock (Kodak, Fuji), and film speed (100ISO, 400ISO, 3200ISO) but they all do the same thing--react to light and imprint the image onto the film via a chemical reaction.
film vs. ditigal
In comparison, digital cameras will capture an image by recreating the image via megapixels. Each image is organized on a grid, and the camera basically assesses each little quadrant within the grid and recreates the colors, form, shape, and lighting digitally and matches to the best of its ability, what's shown in each quadrant of the grid. Thus, the more megapixels (MP) your camera has, the more detailed and crisp your images will be, since it can read and break down the grid into even smaller quadrants.
So, to put it simply: digital photos are a recreation of a moment in time, vs. film, which is that moment literally burned into silver and gelatin.
You can of course create amazing work digitally, but what I love about film is that it isn't art that's been removed from it's source material. It's not a recreation of that image, but rather it IS that image that's been placed in a new location. It feels real, raw, and true to the art being created, rather than a copy of what was seen in the real world.
how to choose the right ISO/film speed
All 3 of these images above were shot on black and white film, but they're all different speeds of film. Depending on the light present, photographers use different speeds. Speed refers to how much light a film allows once the shutter clicks. This of course means that films of different speeds have different chemical makeups, since some will react to more or less light, but for the sake of brevity, let's keep it short and sweet:
Slow speeds = the film is LESS sensitive to light naturally, so BRIGHT situations are needed to fill in the "gaps."
Fast speeds = the film is MORE sensitive to light naturally, so DARKER situations are great for this, since the film itself will fill in the "gaps."
Film ISO usually ranges from 100 ISO-3200 ISO, but you can definitely find speciality film that goes under and over this range.
NOTE: Film speeds also dictate the amount of grain a photo has. The lower the ISO, the crisper the image. The higher the ISO, the more grain you'll have.
50 ISO will be crisp AF. No grain detected to the naked eye.
3200 ISO will be very grainy, but also extremely gorgeous and can add a bit of soft-focus without any Photoshop/Lightroom editing tricks.
It all comes down to your lighting, as well as the amount of grain you're okay with allowing in your photo.
how to know what ISO/film speed to USE
Now we know that low ISOs are for bright, sunny days, and high ISOs are for indoor/nighttime lighting. So with many speeds to choose from, how do you know what is right for your photoshoot?
Here are some general rules of thumb:
100 ISO or lower: BRIGHT, OUTDOOR, SUNNY DAYS! At the beach or an open field and don't have any shade? Pick meeeee.
200 ISO: BRIGHT, OUTDOOR, SUNNY DAYS! There might be some pockets of shade you can shoot in, like tree lines, umbrellas, patios, etc. But for the most part, it's bright and you'll most likely have full-sun exposure.
400-800 ISO: THE PERFECT MIDDLE GROUND. INDOOR/OUTDOOR, WITH AMPLE LIGHT! This is perfect if you're not sure what the lighting will be like for the entire shoot. These speeds can be used indoors and outdoor, in shade, in indirect light, near a big window, or with indoor flashes in a studio. 400 and 800 is my go-to for weddings. It can work inside as the bride gets ready, but also during those gorgeous golden-hour portraits.
1600-6400 ISO: INDOOR/NIGHTTIME! Shooting before dusk? After sunset? At a late-night party with mood lighting? At a concert? Do you love nighttime street photography and milky neon signs? This is your bff.
how to shop for FILM STOCKS
Now that you know what kind of film speed you'll need, there's a wide variety of stores that sell all kinds of brands. This just all comes down to personal preference. People like certain brands for the way certain colors are captured, so do a little research and search a film brand on IG and look for patterns in terms of colors to help you choose what you like.
Fuji is typically very cool-toned, and emphasizes blues and greens.
Kodak is more of warm-toned stock, and will give off a warmer hue. I think it looks the most natural, but that's just me. :)
Kodak Ektar (a sub-genre within Kodak) is GREAT for dark skin tones, whereas with other Kodak film types, like Portra, darker skin tones can look super red.
Ilford makes only black and white film, but there's many sub-genres with their brand, so pick a few and experiment until you find what you like! Some are more contrasted, while others are more muted. I prefer a heavier contrast to my black and white for the drama, so I like their T-Max over their HP-5.
There's a ton of other smaller companies that make film, and from time to time I'll pick up a few rolls to play with. But for the sake of consistency with my work, I stick with Kodak for my color film.
Do your research before a shoot, and know WHO you're shooting, WHERE you're shooting, and WHEN you're shooting. This will ensure you are completely prepared for whatever curve balls are thrown at you, and it also means less editing after the fact, since you'll know the film you chose was the best for the situation.