Is overexposing 1 stop normal?

dylan77

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I have recently moved into shooting film, Currently shooting with Portra 400. Nikon f100

From what I’ve seen on YouTube it seems like overexposing 1, sometimes up to 2 stops is better for a more accurate exposure, than finding the balance (middle of meter), which often leads to under exposure.

Do you guys agree with this?

Thanks
 

markbau

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Bikerider

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No it isn't. Especially with colour negative film. C41 film has such a wide exposure latitude there is no need to over/under expose. If it is over exposed then you do get more saturated colours to a certain extent then there is also a risk of getting what are know as crossed curves in the development stage. This where the different layers start to develop at different speeds and you get colour distortion that is almost impossible to correct

With B&W you will start to block up the highlights and make printing all that more difficult.
 

markbau

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Bikerider said:
No it isn't.

With B&W you will start to block up the highlights and make printing all that more difficult.
Click to expand...

The vast majority of B&W workers routinely give film more exposure than a light meter set at the stated ISO would recommend. If you have highlights that are blocking up (printing as paper white) you need to reduce film development time.
 

perkeleellinen

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Overexposing (like underexposing) is an advanced technique some photographers use to get the picture they want. If you're new to film don't go there - just trust your camera meter, use the ISO which is on the film box and find a relaible lab to send your film to. Practice lots like this before you try new techniques.
 

foc

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The speed of the film on the box is there for a reason.
Shoot at the correct speed, learn the rules and only then can you decide to break them.
No disrespect to Youtube, but just like the net, there is a lot of wrong info put forward as fact.
I have seen lighting ratio incorrectly explained in a photo tutorial and someone using a chopping knife (very dangerously) in a cooking tutorial.
I am probably very old school, I would recommend reading a few photography books for example:
  • Fundamentals of Photography by Tom Ang.
  • The Film Photography Handbook by Chris Marquardt.
  • I am sure other contributors can add their recommendations.
 

Mr Bill

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dylan77 said:
Do you guys agree with this?
Click to expand...

Hi, I don't generally watch that sort of thing on YouTube so don't really know what they're saying.

But a few things you should know about color films. They're made with three different color layers, each sensitive to certain colors. The sensitivities are only matched under the correct light, which is generally "standard" daylight, which is about the same as electronic flash. So if you want a so-called accurate exposure it should be under one of these lighting conditions.

If you use different lighting there's a good chance that at least one of the layers will be underexposed. For example, consider the old style tungsten lights (the sort of light bulb that gets hot). Such a lamp is weak on bluish light relative to reddish and greenish light. In fact, compared to daylight, the bluish light component is only about 20% of the reddish light. If you used a daylight-balanced film like Portra under this lighting, the blue-sensitive layer would likely be underexposed by a stop or two, depending on how your specific meter sees things.

Next major point: color neg films typically include both hi-sensitivity and lo-sensitivity layers in each color. And the hi-sensitivity layers, like high-speed films, are grainy. What this means is that underexposed film is gonna be relatively grainy in the shadow areas. And if you have one color-sensitive layer that is underexposed then that color layer will give grainy results in the shadow areas.

What does this all have to do with you? Well, if you are in daylight lighting conditions then you should be fine exposing according to the meter. If the lighting is deficient in certain colors then you should increase exposure to prevent having one underexposed color layer.

Now, with respect to Portra in particular, my experience has been mainly with the 160 version (I expect that the 400 will behave similarly) under studios lighting conditions. And optically printed. In this situation Portra could go anywhere from about a stop underexposed to 3 or 4 stops overexposed, and if the prints are individually hand-balanced, the color results are so close that you cannot tell them apart. Anybody who is educated on the internet will probably find this hard to believe, but it was done (albeit 10 years or so ago) under very stringent test conditions. I described some of the testing here:
https://www.photrio.com/forum/threa...-of-color-neg-film.168506/page-3#post-2192714

Ps, you should not assume that other color neg films have the same exposure latitude.
 

guangong

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There are many links in the exposure chain: accuracy of meter, accuracy of shutter, nature of scene or subject to be photographed. Each can diverge from perfection. Experiment with one roll by shooting each pic at box speed, then one stop under and one stop over and then decide which results you prefer. I usually go with box speed, but everyone has their own taste.
 

Neil Grant

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...are you sure overexposure can cause crossed curves? This can arise when the exposing intensity is much higher or much lower than anticipated. Most often 'lower', sending the film into low intensity reciprocity failure - specifically 'differential' LI RLF. The separate sensitive layers of the film loose sensitivity at different rates - introducing colour castes that are density dependant.
A 'thin' colour neg is undesirable because it's likely to be grainy compared to one having more exposure.
 

BradS

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I rate Portra 400 at EI 250...about 2/3 stop more exposure that box speed.
 

MattKing

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There is a difference between increasing exposure to ensure good shadow rendition, and over-exposure, which I consider to be a mistake in exposure.
ISO values are designed to ensure good highlight and mid-tone rendition - which is most important to how a print looks.
People who use labs and automatic processing get best results using box speed. People who have the ability to do custom darkroom printing may get more flexibility if they increase exposure, and then adjust the highlight rendition manually at the time of printing.
 

Mainecoonmaniac

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Ilford XP2, a C-41 film could be exposed between 100-400 ASA. Color negative film has a lot of latitude with shooting. Some photographers consistently "over expose" color neg film. It will give a denser negative which isn't necessarily bad as long there isn't any color crossovers. Just experiment and see if you like the look.
 

removed account4

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hi dylan77
it all depends ... for negative film a little extra exposure is always better than not enough
but that said, i would do a few of your own tests with the film to see where your own sweet spot might be.
same scene expose as your meter says then 1 full fstop ( or shutter speed ) extra light, and 1 full stop less light
THEN see how you like the prints or if you do the electric dance see how you like the files.
people's advice of extra stops or less stops works for them but i know i don't have their camera or meter or light or development technique...
have fun !
 

BradS

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I think back to when I was a kid - all those photos that my mom and grandmother took with the Kodak Brownie Hawkeye. It's a very primitive box camera. Importantly, it had one shutter speed and one aperture (something like 1/50 sec and f/8 I suppose). It had no built in light meter and neither grandma nor mom ever used a hand held meter. Yet, somehow almost all of those family snap shots that they took outdoors in full sunlight or indoors with the big, blindingly bright flash bulbs...they all turned out ok and many of the prints still exist today (although the colors have faded). Now that I think about it, all the photos I took outdoors in full sun or indoors with flash cubes with the Kodak Instamatic thingy (one shutter and speed on f-stop) that mom gave me when I was a kid turned out fine too!

There are bigger things to concern yourself with than over-exposing color negative film by one stop.
 

Nodda Duma

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There’s a lot of responses here which don’t quite address your specific film — Portra 400. It is well known that Portra 400 responds favorably to rating slower than box speed. I like to shoot at 200 for the light and airy color rendition that resuls. It’s up to you to determine what EI gives results that you like the best.
 

Andrew O'Neill

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Shoot a test roll and see what works best for you and your equipment/processing. For me...depending on the film, etc... it's usually 2/3rds to a full stop more exposure. You want to get the shadow detail high up on the toe. There have been times where I have given a couple of stops more along with reduced development, to reduce contrast in a scene. Currently, I have been playing around with Ferrania's P30. This is the weirdest film that I have ever used in that I have to give 1 2/3rd stop more exposure to get decent shadow detail. This film is definitely in a category of its own. Cheers and Happy New Year!
 

LolaColor

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Portra 400, like all colour negs, has just over 4 stops below middle grey when exposed at box speed, but unlike some other colour negs it has many more stops above... somewhere in the region of 7 or 8 stops above middle grey until the highlights begin to compress.

4ish stops below doesn't give a whole lot of shadow detail so it makes sense to overexpose slightly. The latitude of negative film is all in the highlights, unlike digital where it is in the shadows.
 

Bikerider

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markbau said:


The vast majority of B&W workers routinely give film more exposure than a light meter set at the stated ISO would recommend. If you have highlights that are blocking up (printing as paper white) you need to reduce film development time.
Click to expand...

I am aware of the need to reduce development with over exposure but that wasn't part of the question. It won't work very well with RA4 because of the crossed curves will not have allowed the developer to work properly and as the standard development time is 3 mins 15 seconds anything less and the operator risks uneven development too.
 
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dylan77

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Thankyou for all your responses. Your advice has been great and very helpful
 

dmr

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logan2z said:
That's my general approach as well. I'd rather overexpose a little in order to retain shadow detail.
Click to expand...

True, and of course we're talking negative film here.

Slides, on the other hand, can't take a joke, exposure-wise, and I almost always bracket if I can.
 

Sirius Glass

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I have used Portra 400 for many years, while it has a wide exposure latitude, stick to box speed until you have a good reason to vary from there stick to box speed.
 
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