Histograms

Without the right knowledge, histograms for all intents and purposes could be as useful as hieroglyphics. This should not be the case for any photographer. In this post I intend to

1) Define Histograms

2) Explain How to Read Histograms

3) Provide Examples of What Histograms Can Show You

1.

Histograms are simply a visual representation (or graph) of data in the file. In particular, histograms try to show you the tonal range of your current photo. Tonal range shouldn't be a scary or confusing term. It just means brightness values- from black to white and the in between. Important to note that it is illustration brightness and not color, although histograms work perfectly well with color photos.

2.

So how am I supposed to read a histogram? 

Above is a histogram from Aperture. You will see histograms all over the place, Photoshop, Lightroom, Magic Bullet etc.

These are the three things you need to know:

      The left hand side of the histogram represents the black.

      The right hand side of the histogram represents the white.

      The height is simply the concentration in the tonal range.



 

3.

This first histogram is telling us the following:

The left side of the histogram has a high proportion- meaning the black. It would be safe to guess that this photo is underexposed, or has a large amount of shadows.

The rest of the histogram is relatively flat, not indicating a large range. It is possible this photo would appear flat, not too dynamic in tones.

The tones cut off before they reach the right. Indicating no white tones will be in the photo.

This second histogram is:

A mountain shape. There is a myth that this is the ideal shape, but every photo is different and this is not true. What mountains indicate is there is a dynamic range of tones.

The left side doesn't begin until a quarter in. Meaning no dark tones. It might be a good idea to enhance the contrast or shadows.

This third histogram is:

A large amount of tones are on the right side, indicating a lot of white tones in the photo. In this photo you could expect a lot of bright whites.

The rest of the tones exists on the first half of the histogram (closer to the black) meaning the tones are either very bright or very dark with little in between. 

While going through these examples you will notice that nothing is for sure. These are always good guidelines for when editing photos. What is also helpful is if you adjust the contrast, saturation etc, the histogram will change accordingly. Don't look for the perfect histogram, but when unsure what needs to be tweaked always look to the historgram.

Photoshop/Indesign CS6: The RAW

In this post I intend to introduce the skinny on RAW, particularly..
1) what a RAW format is
2) advantages of using RAW
3) disadvantages of using RAW

RAW?
A RAW file format is an unrendered format that has not been modified or compressed. You can think of them as the higher quality brother of JPEG or TIFF. Sometimes referred to as a 'digital negative', due to its likeness in negatives with film photography because it holds all the information of the original photo and you can create many different copies (or versions) for it.

BENEFITS

 1) Quality!- Due to the lack of modification or compression RAW file formats are the highest quality choice. No lossless compression means no compression artifacts. This also means higher bit depth, dynamic range and exposure compensation.

2) RAW format is nondestructive- that is only the metadata that controls the rendering is changed. Just like using a film negative this digital negative will hold all the information so that you can create as many versions as you like!

DRAWBACKS

The drawback of using a RAW format is primarily the size of the file (since they are typically 2-3 times larger then the JPEG version) and that RAW files are not universally standardized. This standardization issue isn't so much of a contemporary concern but a future concern, as hardware and software rapidly changes photographers worry not all computers will be able to access the RAW format. You may have seen DNG file types before, it stands for Digital Negative Group and was an attempt made by Adobe to address this concern by trying to create a 'universal RAW format'.

Photoshop/Indesign CS6: The JPEG

In this post I intend to clarify:
1) what a jpeg is
2) how a jpeq's quality can be manipulated in Photoshop/Indesign.



JPEG/JPG is a very popular file format for digital photography. It stands for Joint Photographic Experts Group (that's a kicker huh?). It is a lossy compression method that can be compressed based on one's needs. Lossy compression in I.T. terms simple means it can become smaller by losing data (thus by losing quality).

When using Photoshop or Indesign one will notice a choice when exporting or saving a JPEG file. It depends on what you are using but it should look something like this:

Either in qualifying terms like 'low, medium, very high' or a quantitative scale from 0-100. Either way when choosing the size it is important to understand that choosing a lower quality will sacrifice the quality- so unless it is necessary for size purposes- DON'T DO IT!


Here is an example of a jpeg file (zoomed in at 300%) at the highest quality versus the lowest quality.

Notice the grid like pixels that are more clearly defined in the second photo. This JPEG has lost some of the data once associated with it and now shows what photographers call digital artifacts. To avoid artifacts it is extremely important when saving to maintain the highest quality standards.  

Indesign CS6: CMYK versus RGB

In this post I intended to explain
1) the differences between CMYK and RGB
and 2) how this affects ones work within programs like Indesign.

Key Terms:
CMYK: Cyan, Magenta, Yellow and Key color model used in printing.
K (key): refers to black
RGB: Red, green and blue color model of what a computer screen uses.

Color models are very important as they dictate how color is reproduced in print and in web form. There are two dominant models that you will encounter CMYK and RGB. CMYK is a subtractive color model while RGB is an addictive color model.  You can think of this as pigments (like a painting) versus lights (like the pixels on this screen). When it boils down to it, it means that the blue one could choose in CMYK will not reproduce exactly in the RGB. Why does this matter for you?

Well put simply you will have to make a choice while using programs like Indesign. A decision that needs to also be influenced on how you intend to disperse your work (printed or digitally).

When you decide to open Indesign and go to the swatches you will see a menu that looks like the following:

Interestingly enough, all of the colors depicted here on the screen are being created by the RGB lights of ones screen but are displayed in a CMYK format because Indesign assumes you would like to print these colors. On closer examination you'll notice the red, green and blue selections aren't so great. I recommend deleting them (yes delete them) and find shades of those colors that are more pleasing for your purposes. To delete those colors have no document open, click on the bad colors holding the shift key to highlight and click the trash icon on the bottom right.

If, however, printing is not an important influence and you would indeed like to choose colors from the RGB model you can! Click the most right hand icon on the top of the swatches bar, click new color swatch and you'll be brought to a panel that looks like this:

You'll notice in this new panel there are tons of new color models to choose from. Although I won't explain all of them let me give you some info for future reference or just plain curiosity.

   Pantone: a standardized color system like CMYK that uses up to 13 base pigments and
    can generate metallics and fluorescents that can't be produced by CMYK.

   TRUMATCH: uses a simplified four color system and handles the black separately from
    theCMYK.

  HKS: contains 120 spot colors and like Pantone produces colors that can't be produced
   by CMYK.

Pantone in particular will be a future subject for discussion. But for now the key is to understand the different defaults for print and digital media and what that means for your use in the CS6 suite.

Photoshop CS6: HDR Workflow

This post is intended to cover two topics:
1) what is HDR
and 2) how to create HDR photos through Photoshop CS6.

Key Terms :
HDR/HDRI : High Dynamic Range Imagining.
EV : exposure value, (referring to a combination of the camera's shutter speed and aperture),
commonly referred to as 'stop'.
Ghost Artifacts : duplicated objects in the frame that appear right next to one another.


So what is HDR? If you have been just dabbling in photography or a long time photographer you may have noticed the hype surrounding the word HDR in smart phone ads and point and shoot cameras. (Although the practice itself originates from the 19th century!) It stands for High Dynamic Range, or High Dynamic Range Imagining, in which multiple exposures of the same shot in varying EVs are taken to allow a greater range of darker and lighter intensities. It essentially is a way to compensate for the cameras inability to capture the full range of intensities by intellectually stitching together different exposures.

Why is this ideal? Well HDR photos are better able to preserve and depict the diversity of luminance that more accurately reflect the real world. While this might not always be ones desired effect, it is great knowledge to know.

Many inexperienced photographers/editors (including myself at one point) tried to imitate this look by slamming the saturation, adjusting the curves to strengthen the dark and light spectrums and calling it good. This is not the same.

The good news is that creating HDR photos doesn't have to be an impossible or difficult process. Using merge to HDR pro built in to photoshop CS6 I will show you the simple steps to achieving HDR quality.

Step 1: Choose your images!

Ideally choose three images with varying EV values. It is encouraged so that each photo is near identical that you use a tripod or some sort of stabilizer when you take the photos (this is not an absolute). The three EV values should reflect a darker, a mid range and a highly exposed image to cover the range. You may find with practice this becomes easier. Another tip is if your computer you are using is a little older (or just doesn't have the ideal RAM) you can use two images so the process isn't as dreadfully slow as a slug.

Another thing to note is that differing HDR software will have different processing settings. In this format do not tweak the photos before doing this! It will make it harder for the three photos to look the same. The most you would want to do is maybe adjust the white balance and noise but make sure this is consistent with all three photos!

Step 2: Open Photoshop and begin 'merge to HDR pro'.

Go to 'file', then 'automate' then click 'merge to HDR pro'. It will ask you to either choose the files or folders. Choose accordingly the three exposures you want to work will.

Once those files are selected and added to the dialogue box make sure that 'attempt to automatically align source images' is checked. This will be particularly helpful if you did not have a tripod to stabilize your shots.

Click 'ok'.

Photoshop will get to work and create layers for each exposure selected. When done a dialogue box will open. You will likely have to realign the box a bit but what you should see is your composited image in the center, three thumbnails of the images below and a preset bar on the right side.

Step 3: Use 16 bit mode to get the most out of the UI settings.

You may notice on the right hand side it has chosen 32 bit mode for the UI settings. To get the most control choose 16 bit in the 'local adaptation' and you will notice edge glow, tone and detail and advanced options appear.

You may notice a preset bar at the top. Go ahead and play with it, but like any plug in or preset don't just pick a preset and call it good. Each photo will be different and require a customization of these presets. Don't be lazy- unless you have to...

Step 4: Get rid of those ghosts! (Ghost artifacts that is).

It will be inevitable, especially as more and more images are used that ghost artifacts will emerge. Ghost artifacts can occur when movement of objects between exposures happens. For example the breeze blows a branch slightly in a different place, or the flow of water, or movement of anything in general causes what appears like duplication. It will create this blurry messy artifact that you will want to be rid of. So be rid of it!

You will want to choose anyone of the thumbnail exposures below. It is usually recommended that you choose EV 0 as the base exposure for removing ghosts. Go ahead and choose it and check 'remove ghosts' on the right hand corner. It will take photoshop a second to process and viola! If it doesn't look right you can uncheck and try a different exposure.

Step 5: Use Edge Glow, Tone and Detail and Advanced to edit the final product.

I can not tell you exactly what setting you will need for each. What I can tell you is how each setting is designed to function. If you forget any of this remember that hovering your cursor over each setting will give you a general description and you will always get a preview!

Edge Glow: identifies high contrast areas in the photos and allows you to boost the glow while still maintaining detail to the photo. It is measured by radius which is essentially the boundaries of the glow effect. The strength would therefore be an intensity setting for the radius. (Warning: too much strength can blow out the photo). Experiment with edge smoothness to counter this.

Tone and Detail: controls the global brightness and the overall detail of the HDR look. Too much gamma can flatten out the image.

Advanced: gives you shadow, vibrance, highlight and saturation controls.

Step 6: Hit 'ok'

And there is your HDR image.


***photos to come!