PrintThere are several types of charting methods, but three of them are the most popular.
Bar Chart
In a bar chart, a vertical line is shown for each time increment selected. In the chart below, a “daily” chart is used to show the May NYMEX contract for natural gas. Each bar shows the price results for that day’s trading. The mark to the left of the bar represents the first trade of the day, or the “Open.” This is the price of the first trade that occurs right after the bell rings to start trading. The vertical line itself represents the full range of prices for the day, that is, the High and Low prices. And the mark to the right of the bar represents the final closing, or “Settlement” price for the day. This is often referred to as the "OHLC" chart (Open/High/Low/Close). Note that if the Open price is lower than the Close, the bar is green. If the Open price of the day is higher than the Close price, the bar is red. It shows the direction of the market movement; do prices tend to go up or down?
So, I'm gonna click on the chart icon. This is the third column from the left, right beside the last, and we will focus on it. I click here to launch in a pop-up menu or a new window. This is May 2020 crude oil futures.
Okay, let me clean up the chart a little bit. I removed the information that we don't need for now. We'll add them later. So, this is the chart. As you can see, the vertical axis is the price. This is dollars per barrel of crude oil. You can change the limit of each of the axes. You can click on the axis, hold the click, and move it up and down, and it changes the range of the axis. It's the same for the horizontal axis, which is time. Click, hold, and move it to the left and to the right. You can also use these features: you can zoom in, you can zoom out, you can move to the left, you can move to the right, or you can refresh the page. You can restart the page. So, this updates. This is the real-time data. We can see this price changes quickly, and once in a couple of seconds, we'll get some new information.
Okay, I'm gonna zoom into more recent data, and we'll go through some of the... So, you are familiar with this type of chart. This is called a bar chart, and we have it. We can clearly see it here. This is... There are multiple pieces of information that are represented. These are presented by each of these bars. So, we should be able to read five pieces of information. Each bar should give us five pieces of information. So, what are those pieces of information? Open, close, high, low, and the trend, which is the color, right, on that day.
For example, let's start from one of these. Let me zoom a little bit to be able to see this. Let's, for example, talk about this. This is March 25th, 2020, and we can see this is a bar. There is this left little tick or little line here, there is one on the right. The bar has some lower part here and the bottom and top of the bar. So, what is the left? The left line, this is sticking to this bar, is the open, right? The right is the close, right? And the top part of each bar is the highest price being traded on that date, and of course, the lowest part is the low. So, if you move the pointer to any of these bars, you can see these numbers up here. They will get updated. For example, here, this is March 25th, and as you can see up there, open was $24.37, high is $25.24, low, close, and percentage change.
Okay, there is another piece of information that is being shown here, and that's the color of these bars. You can see that they come in two colors, green and red. What is the difference? As you can see, if the open on that day is lower than the close, or if the close is higher than the open, this bar is green. If the close is lower than the open, the bar is red. What does it tell us? It tells us the trend of the price on that day. For example, these are the last five business days. We can see it opened high, it closed low. Opened high, closed low. Opened high, closed low. And including today, open and close are fairly around the same value, but this is red. It is telling us that the close is lower than the open. So, if this close goes a little bit higher, if it passes the open, this bar will turn green.
So, the five pieces of information that we get from each of these bars are open, high, low, close, and the trend of the day.
Style of Charts
You can change the style of the chart and type of information that you want to be displayed by clicking on the Bar Style toolbar 
and selecting from the list of chart options which include things like bars, candles, line, area, and point & figure. The image below is an example of a “Line” or “Close Only” chart showing the same May natural gas contract. You will notice that it only shows the daily market closing (settlement) price. It provides much less information than the Bar chart and is mainly used for longer-term trend analysis.
Candlestick Charts
Candlestick charts were developed by the Japanese centuries ago. They provide information similar to the Bar chart, but also indicate “up and down” days. That is, they clearly show the direction the market took on a daily basis. The top end of the “candle” still represents the "High" for the day, and the lower end represents the “Low,” but the “body” indicates the Open and Closing prices in relation to one another. For example, if the Open is higher than the Close, the Open price is at the top of the “body” of the candle and represents a day where prices fell (red candle). Conversely, if the Close is found on the top of the “body,” it represents an “up” day, and on the chart below, appears with a green “body.” As you can now see, the up-and-down days are easily visible on the Candlestick chart. By counting these, we can determine the current trend. For traders, the question is, when will it reverse course?
Let's move to the next chart. How do we change the chart? So, up there, there is a chart icon. The next one is the second most common chart, the candlestick chart. On the top part of the chart, you can find them here. These are under chart options, and I select the candle. Okay, the candle is another type of chart. This is very common in finance. Again, this gives us each candle for each day. It gives us five pieces of information, but this one is a little bit tricky compared to the bar chart. Each bar is going to tell us five pieces of information: open, high, low, close, and the trend of the day.
But here, we don't have that left line and right line. We have the upper part of the candle, the lower part, and the actual candle top and bottom. So, these are four. So, how do we know which one is open and which one is close? That's indicated by the color. If the color of the candle is red, then the lower part of the candle is close, and the upper part is open. If the color of the candle is green, then the lower part is open, and the higher part is close. You can double-check that by moving the pointer to that candle. You should be able to read it up here. Let me move it to a pointed point on the candle, and you can read it from there.
So, on this day, March 23rd, the open is $22.52, the low is $20.80, the high, which is the very top part at the end of this line, is $24.70, and the close was $23.36. You move this pointer around. The lower part of the chart, the x-axis, shows you the day. You track this line, and you will see this is March 27. The right-hand side shows you the price. You move it to this top part, and you can see this is $23.30. This is around the high, which, sorry, this is the close that we can read from up there.
One of the biggest problems with this chart is it needs a color printer to be able to read the low and high because if you print this in black and white, these two will look the same. So, how do we know which one is open and which one is close if you need to know the open and close? There is another type of candle chart called the hollow candle. This is for the time that if you are going to print it in a black and white printer, if you have the hollow candle, it means that it's the same as the green color. So, if you have a hollow candle, it means that the trend that day was upward. So, the lower part of the candle is open, and the top part of the candle is close. If the candle is filled, in a black and white printer, it will look filled black. If that's black, then the trend is going to be downward. So, the top part of the candle is going to be open, and the bottom part is going to be close. This is the only difference, but this is a very common chart, and you just need to know when we read the open from the top and when we read the close from the bottom.
There is another chart that simplifies this. If you are not very interested in what happened that day and you want to have only one single price for that day, you will just add a line. You can add it by, and you're more than welcome to open the chart and do this with me. You go to the top part of the chart, from this little arrow, you pick the line. If you pick a line, you will get a single line for each day. How do we know which price this line is reflecting? Is it open, close, high, or low? By default, it is close.